asan failure calling process_sync_test and signals_test

[dcharkes]

Tests reliably failing on the build farm, but not reproducible locally:

python tools/test.py -m release -n dartk-asan-linux-release-x64 standalone_2/io/process_sync_test
python tools/test.py -m release -n dartk-asan-linux-release-x64 standalone_2/io/signals_test

Both tests expect a process exit code <0> but got exit code <1>.

https://github.com/dart-lang/sdk/blob/master/tests/standalone_2/io/process_sync_test.dart#L38
https://github.com/dart-lang/sdk/blob/master/tests/standalone_2/io/signals_test.dart#L65

Builder vm-kernel-asan-linux-release-x64

Tests succeed without asan.

[mkustermann]

Marking as duplicate of #34724. These tests spawn subprocesses and the subprocesses report asan leaks, which makes the exit code probably 1 (the asan default)