runtime: TestRaceSignal fails on darwin/amd64

[bcmills]

From https://go.dev/cl/488115/2:
(https://storage.googleapis.com/go-build-log/b78b8a6c/darwin-amd64-longtest_f3d02d13.log):

--- FAIL: TestRaceSignal (5.12s)
    crash_cgo_test.go:428: Hung for 5 seconds
        
    crash_cgo_test.go:429: exit status 1
FAIL
FAIL	runtime	554.054s

[bcmills]

(This test was skipped on darwin until https://go.dev/cl/487575; attn @ianlancetaylor.)

[gopherbot]

Change https://go.dev/cl/494456 mentions this issue: runtime: remove crash_cgo_test CgoRaceSignal timeout