Several of our tests make use of numbers without an exact floating point
representation (frequently 0.x where x!=5) which, when scaled, also
scale the error. The end result is that some of these tests currently
implicitly rely on an implementation detail of floating point math and
are sensitive to differences in the ~15th decimal place.

This patch reduces the sensitivity of some of these tests, checking
values using `moreOrLessEquals` from the flutter_test package
rather than requiring en exact match.

This reverts commit 12b7355d.

Reland "Prevent viewport.showOnScreen from scrolling the viewport if the specified Rect is already visible. (#56413)" reverted in #64091 (#64513)

This reverts commit eef0050d.

* 97f9f712b [web] Fix analyzer warnings in web engine. (flutter/engine#20825)

* dcb9244c3 Consolidate FlRenderer initialization into fl_renderer_start() (flutter/engine#20763)

* 80f68fd60 Roll Fuchsia Linux SDK from lqjGEhKFW... to kbanTZZRS... (flutter/engine#20830)

* 0491b6c7d Roll Fuchsia Mac SDK from fqYfP5y9V... to tG1GErEv9... (flutter/engine#20831)

* 195b1480d Roll Skia from 55f02eb3ff5f to ee58da9d6f49 (7 revisions) (flutter/engine#20832)

* 25a23baee [fuchsia] Add fuchsia_ctl func to test script (flutter/engine#20827)

* 095e5d368 Roll Dart SDK from b0f6d5483b79 to 8e50ccae259f (2 revisions) (flutter/engine#20834)

* be21aa992 Roll Skia from ee58da9d6f49 to 716e281185b5 (2 revisions) (flutter/engine#20835)

* 808f9c27e Roll Skia from 716e281185b5 to 952f088d41e1 (1 revision) (flutter/engine#20839)

* 1a034bde7 Replace FlRenderer::get_visual() with more generic FlRenderer::setup_window_attr() (flutter/engine#20833)

* e67ae1e30 [web] Fix path rendering when addPolygon is chained with other verbs. (flutter/engine#20803)

* 3ccf1ed2e Cliprect op (flutter/engine#20837)

* 52def6e88 Roll Dart SDK from 8e50ccae259f to ac54810c36a9 (1 revision) (flutter/engine#20844)

* 8e16dbf4a Roll Skia from 952f088d41e1 to d385091edd58 (4 revisions) (flutter/engine#20847)

* 81a4748d6 Roll Dart SDK from ac54810c36a9 to 066c5625ac7b (1 revision) (flutter/engine#20849)

* cca047b2c Roll Fuchsia Linux SDK from kbanTZZRS... to jyKllAGRu... (flutter/engine#20851)

* 0208c71ad Roll Fuchsia Mac SDK from tG1GErEv9... to koO5t2tfw... (flutter/engine#20850)

* 5b3a16c5a Roll Dart SDK from 066c5625ac7b to fe5c8c44701e (1 revision) (flutter/engine#20854)

* 3f4f58f5f Roll Skia from d385091edd58 to 8a43e206609e (3 revisions) (flutter/engine#20855)

* Reland "Re-enable the Dart Development Service (DDS) (#64671)"

This reverts commit 2ae25cc2.

* Fix MDNS building Observatory URI with port 0 instead of forwarding the device port

* Added MDNS test

This reverts commit ce9cde8c.

This reverts commit e8252817.

This reverts commit d7d12412.

This change re-enables DDS and outputs the DDS URI in place of the VM
service URI on the console. If --disable-dds is not provided,
--host-vmservice-port will be used to determine the port for DDS rather
than the host port for the VM service, which will instead be randomly
chosen.