[flutter_tool] Kill a timing-out process before trying to drain its streams

[zanderso]

Description

This PR fixes a test of subprocess timeout behavior such that its stdout and stderr streams won't be completed until the subprocess is killed. The corrected test required that runAsync() be fixed to kill a subprocess before trying to drain its output streams. I also made runAsync() only try to drain the output streams of a killed process for a second or so to handle the case where the attempt to kill the subprocess is unsuccessful for some reason.

Related Issues

#35988

Tests

I added the following tests:

Updates to process_test.dart

Breaking Change

Does your PR require Flutter developers to manually update their apps to accommodate your change?

• Yes, this is a breaking change (Please read [Handling breaking changes]). Replace this with a link to the e-mail where you asked for input on this proposed change.
• No, this is not a breaking change.

[codecov]

Codecov Report

Merging #40159 into master will decrease coverage by 0.45%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #40159      +/-   ##
==========================================
- Coverage   58.51%   58.06%   -0.46%     
==========================================
  Files         192      192              
  Lines       18426    18416      -10     
==========================================
- Hits        10782    10693      -89     
- Misses       7644     7723      +79

Flag	Coverage Δ
#flutter_tool	58.06% <100%> (-0.46%)	⬇️

Impacted Files	Coverage Δ
packages/flutter_tools/lib/src/base/process.dart	83.43% <100%> (-1.08%)	⬇️
...flutter_tools/lib/src/android/android_console.dart	0% <0%> (-96.3%)	⬇️
...ckages/flutter_tools/lib/src/base/fingerprint.dart	54.66% <0%> (-40%)	⬇️
packages/flutter_tools/lib/src/cache.dart	22.46% <0%> (-21.77%)	⬇️
.../flutter_tools/lib/src/android/android_device.dart	15.75% <0%> (-18.25%)	⬇️
packages/flutter_tools/lib/src/device.dart	55.88% <0%> (-2.36%)	⬇️
packages/flutter_tools/lib/src/version.dart	90.9% <0%> (-1.92%)	⬇️
...ges/flutter_tools/lib/src/android/android_sdk.dart	77.15% <0%> (-0.75%)	⬇️
...utter_tools/lib/src/build_runner/build_runner.dart	0% <0%> (ø)	⬆️
... and 9 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 03e8100...9c610be. Read the comment docs.

[jonahwilliams]

LGTM

[tvolkert]

LGTM