internal/trace: stress tests triggering suspected deadlock in tracer

[gopherbot]

#!watchflakes
default <- pkg == "internal/trace" && test ~ `TestTrace.*/Stress` && log ~ `signal: killed`

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestTraceStressStartStop/Stress
    exec.go:213: test timed out while running command: /home/swarming/.swarming/w/ir/x/w/goroot/bin/go run testdata/testprog/stress-start-stop.go
    trace_test.go:615: signal: killed
--- FAIL: TestTraceStressStartStop/Stress (806.78s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "internal/trace" && test == "TestTraceStressStartStop/Stress"

2025-03-07 19:32 gotip-linux-amd64-longtest-noswissmap go@b4a333fe internal/trace.TestTraceStressStartStop/Stress (log)

=== RUN   TestTraceStressStartStop/Stress
    exec.go:213: test timed out while running command: /home/swarming/.swarming/w/ir/x/w/goroot/bin/go run testdata/testprog/stress-start-stop.go
    trace_test.go:615: signal: killed
--- FAIL: TestTraceStressStartStop/Stress (806.78s)

— watchflakes

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
default <- pkg == "internal/trace" && test == "TestTraceStressStartStop/Stress"

2025-05-02 17:28 gotip-darwin-arm64-longtest go@1b40dbce internal/trace.TestTraceStressStartStop/Stress (log)

=== RUN   TestTraceStressStartStop/Stress
    exec.go:213: test timed out while running command: /Users/swarming/.swarming/w/ir/x/w/goroot/bin/go run testdata/testprog/stress-start-stop.go
    trace_test.go:615: signal: killed
--- FAIL: TestTraceStressStartStop/Stress (2550.43s)

— watchflakes