Follow-up comments to #15984

This updates AppContext per the recommendations in #15352

Fixes #15352

* Add to Artifacts, and add optional arguments to entry points for flut… (#15185)

Add to Artifacts, and add optional arguments to entry points for flutter run and test to allow for wiring up the same with preview-dart-2 internally

* Changing packages uri here is not necessary

This reverts commit e0f6e626.

Add to Artifacts, and add optional arguments to entry points for flutter run and test to allow for wiring up the same with preview-dart-2 internally

* [tools] consolidate "preview Dart 2" option in BuildInfo

* format BuildInfo constructor

accidentally missed due to named parameters being omitted.

* Revert "Revert "Add android license verification to doctor and some refactoring" (#14727)"

This reverts commit d2602947.

* Add tests, fix sdkManagerEnv and use it consistently, and rearrange Status object model

* AnsiSpinner needs to leave the cursor where it found it.

* fix tests

* Const constructor warning only shows up on windows...?

* Avoid crash if we can't find the home directory

* Make pathVarSeparator return a string in the mock

* Implement review comments

* Fix out-of-order problem on stop

- Remove redundant strong flag as it is the default for preview-dart-2
now

* Created plumbing but has stream problem

* testing with makePipe

* Trying pipe but not really getting anywhere

* works by repeatedly reading line

* Minor cleanup

* works

* Clean up pipe after use.

* Move the last status forward

* Make sure failed script commands bubble up

Reports from that commit included:

* Doctor hanging
* Doctor prompting to install JDK
* AnsiStatus.cancel() printing elapsed time and extra newline
* Printing extra spinner character at the end of each line

* Initial version, seems to work

* Unit test for android license checker

* Cleanups

* Windows analyzer wants const.

* Refinements to timeout

* review comments

* Forgot a nit

* Reject requests for hot reload if a hot reload is already in progress.

Fixes #14184

* Implement TODO, verifying further hot reloads complete sucessfully.

* Fix year on new file.

* Add missing type annotations to fix lints

* Add run_machine_concurrent_hot_reload to manifest for CI

* Reformat document

... but undo things that cause lints (like single-line ifs)

* Extract std stream transformations

* Make inProgressHotReload private

* Disallow all types of reload while hot reload in progress

* Simplify code handling in-progress hot reloads

* pass through preview-dart-2, strong, ipv6 in daemon mode

* ws change to kick the windows bot

* send 'reloadRecommended' info to IDEs

* rename hint ==> hintMessage

* tweak the text for the 'elements didnt reload' message

* review comments

* prefix items with a list char

* add a hostIsIde param instead of the isDaemonMode top-level function

* add a trailing comma

* round 2

* deal with null futures

* review

* review

* review

* review

This reverts commit 8d07d3f6.

This reverts commit b2909a24.

This resubmits the following patches:

1. Use Xcode instruments to list devices (#10801)
Eliminates the dependency on idevice_id from libimobiledevice. Instead,
uses Xcode built-in functionality.

2. Make device discovery asynchronous (#10803)
Migrates DeviceDiscovery.devices and all device-specific lookup to be
asynchronous.

* Revert "Make device discovery asynchronous (#10803)"
This reverts commit 972be9c8.

* Revert "Use Xcode instruments to list devices (#10801)"
This reverts commit 37bb5f13.

This is to resolve a failure that looks related to a bad install of Xcode 8.0
on our build bots and should be reinstated when the infra issue is diagnosed
and resolved.

Instruments worked well when this was originally landed, and on the
following commit, but started failing two commits after this originally
landed. Manual invocation of instruments on the build host currently
results in:

```
dyld: Library not loaded: @rpath/InstrumentsAnalysisCore.framework/Versions/A/InstrumentsAnalysisCore
  Referenced from: /Applications/Xcode8.0.app/Contents/Developer/usr/bin/instruments
  Reason: image not found
Abort trap: 6
```

It appears the /Applications/Xcode8.0.app/Contents/Applications
directory (which contains Instruments) is missing on the host.

Migrates DeviceDiscovery.devices and all device-specific lookup to be
asynchronous.

* have app loggers log to their parent logger

* rename field to parent

* add todo

* revert flutter_tools.iml change

* ping the bots

Spawned from a discussion in https://github.com/flutter/flutter-intellij/pull/1003

This message will be picked up by IntelliJ and shown to the user in a toast.

* Let printError print bold as well

* review notes

* add a regression test for daemon device notification

* revert event send simplification