Fair amount of typos spotted and fixed. Some of them are in comments, some of them are in code and some of them are in nondart files.

There is no need for issues since it's a typo fix.

I have doubts about [packages/flutter_tools/lib/src/ios/core_devices.dart](https://github.com/flutter/flutter/compare/master...anisalibegic:flutter:master#diff-fdbc1496b4bbe7e2b445a567fd385677af861c0093774e3d8cc460fdd5b794fa), I have a feeling it might broke some things on the other end, even though it's a typo.

**What has been done?**
----------------------
Added new enumeration in `TableCellVerticalAlignment`, which sets the cell size to the same as the topmost cell. There are no noticeable problems in using it in all cells together, as there are in `TableCellVerticalAlignment.fill` which is made not to be used in all cells together because it has another purpose.

**Explanation of the logic**
----------------------
An assignment was made (which already existed in `TableCellVerticalAlignment.top; middle and bottom`) that assigns `rowHeight` the maximum double between the initialized height and the height of its child.

![image](https://github.com/flutter/flutter/assets/69699209/0fc9c168-5638-494b-aa0c-c579d0494c5e)

Basically, defining a minimum cell height based on its child, and letting each table row have its own height stipulated from the largest element, creating an `IntrinsicHeight` for TableCell automatically.

![image](https://github.com/flutter/flutter/assets/69699209/488b258a-3d25-4655-a9a0-381680468dec)

As the `TableCellVerticalAlignment` logic already provides for the use of the height of the largest cell in the row, it was possible to reuse this logic, and just not make the break statement that exists to fill in the calculation for `intrinsicHeight`.

Real example in an Android application after added enumeration
----------------------
![image](https://github.com/flutter/flutter/assets/69699209/51dce88d-f0f5-4644-942a-11ad218ffca0)

Opened issue
----------------------
FIX: #130261

Fixes https://github.com/flutter/flutter/issues/59413

This relocates `mock_canvas.dart` and `recording_canvas.dart` from `flutter/test/rendering` to `flutter_test`. 

The testing functionality afforded by mock_canvas should be available to everyone, not just the framework. :)

mock_canvas.dart needed a bit of cleanup - things like formatting and super parameters.

Fixes https://github.com/flutter/flutter/issues/131467

An error in the flex methods of min and max column width would produce different results based on the position of the widths that were provided:
`MaxColumnWidth(a, b) != MaxColumnWidth(b, a)`

This fixes that.

This reverts commit 5fd259be.

Migrate framework tests for rendering, semantics, widgets to null safety.

* add language version 2.8 in packages/flutter

* enable non-nullable analyzer flag

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs

Added diagnostic output for needsCompositing to RenderObject diagnostics output.

RenderTable._computeColumnWidths() had a logic error that caused flex columns to be collapsed to their minimum widths in certain situations dependent on the layout width constraint and the number of flex columns.

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

Prevent header from thinking it can wrap and then overflowing.

Fix default footer string which lost its colon (localized values are fine).

Make the "rows per page" drop-down include at least one value even when the table lacks many items. (Previously it would assert if your table was too short.)

Make the footer scrollable.

Fix some todos and improve some debug output.

Tests for much of the above.

Add more tests, fix docs, fix painting bugs...

Fixes https://github.com/flutter/flutter/issues/12902

Also, fix asserts in TableBorder#paint to match documentation.

Fixes #12009

Diagnostics object is.

Refactor RenderObject.toStringDeep and Widget.toStringDeep code to use DiagnosticsNode.

* Switch existings tests to use equalsIgnoringHashCodes and add more tests.

We used to rely on BoxConstraints.deflate's clamping, but now we have to
roll our own.

+ Add new demo to gallery to show data tables. (This currently doesn't
use a Card; I'll create a Card version in a subsequent patch.)

+ Fix checkbox alignment. It now centers in its box regardless.

+ Add Colors.black54.

+ Some minor fixes to dartdocs.

+ DataTable, DataColumn, DataRow, DataCell

+ RowInkWell

+ Augment dartdocs of materia/debug.dart.

+ DropDownButtonHideUnderline to hide the underline in a drop-down when
  used in a DataTable.

+ Add new capabilities to InkResponse to support RowInkWell.

+ Augment dartdocs of materia/material.dart.

+ Add an assert to catch nested Blocks.

+ Fix a crash in RenderBox when you remove an object and an ancestor
  used its baseline. (https://github.com/flutter/flutter/issues/2874)

+ Fix (and redocument) RenderBaseline/Baseline.

+ Add flex support to IntrinsicColumnWidth.

+ Document more stuff on the RenderTable side.

+ Fix a bug with parentData handling on RenderTable children.

+ Completely rewrite the column width computations. The old logic made
  no sense at all.

+ Add dartdocs to widgets/debug.dart.

+ Add a toString for TableRow.

- Add x and y to the parent data, in case it's useful. In point of fact,
  I ended up not needing it.

- Make columnWidths settable rather than having a setter so that the
  code in the widgets layer is more idiomatic.

- Teach setFlatChildren about avoiding unnecessary drop/adopt loops.

- Assert that the child list length is correct more aggressively so that
  we catch the dumb bug I had more quickly next time.

- Improve the toString() to handle empty tables better.

- Resort the imports in framework.dart.

- Introduce a LocalKey for cases where you don't want to allow use of
  GlobalKey.

- Make inflateWidget and deactivateChild public for subclass use.

- Table widget.

- Cell widget.

- TableRow fake widget.