Revert "Fix remaining holes in stack trace demangling"

[dnfield]

Broke the tree, Reverts #60478

tbr @PixelToast

Here's a failure example: https://cirrus-ci.com/task/6707176263647232

Relevant log section:

Failed to precompile tester:tester:
/root/.pub-cache/hosted/pub.dartlang.org/tester-0.0.1-dev9/lib/src/runner.dart:107:5: Error: 'unawaited' is imported from both 'package:meta/meta.dart' and 'package:pedantic/pedantic.dart'.
    unawaited(_process.exitCode.whenComplete(() {
    ^^^^^^^^^
/root/.pub-cache/hosted/pub.dartlang.org/tester-0.0.1-dev9/lib/src/runner.dart:174:5: Error: 'unawaited' is imported from both 'package:meta/meta.dart' and 'package:pedantic/pedantic.dart'.
    unawaited(_process.exitCode.whenComplete(() {
    ^^^^^^^^^
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
ERROR: Last command exited with 1 (expected: zero).
Command: ../../bin/cache/dart-sdk/bin/pub global activate tester 0.0.1-dev9
Relative working directory: packages/flutter_tools
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━```

[jonahwilliams]

This was not caused this PR.