runtime: frequent TestSemTableOneAddrCollisionLinear failures since 2022-06-16

[bcmills]

##### GOMAXPROCS=2 runtime -cpu=1,2,4 -quick
--- FAIL: TestSemTableOneAddrCollisionLinear (0.02s)
    testenv.go:461: [/workdir/tmp/go-build3951896734/b001/runtime.test -test.v -test.run=^TestSemTableOneAddrCollisionLinear$ -test.benchtime=1x] exit status: exit status 1
    testenv.go:490: exit status 1
    testenv.go:491: --- subprocess output ---
        === RUN   TestSemTableOneAddrCollisionLinear
            testenv.go:528: failure to scale linearly: µ_1=201.217µs µ_2=637.562µs p=0.000000
        --- FAIL: TestSemTableOneAddrCollisionLinear (0.02s)
        FAIL
FAIL
FAIL	runtime	596.034s

greplogs -l -e 'FAIL: TestSemTableOneAddrCollisionLinear'
2022-06-17T15:02:55-6c25ba6/linux-386-longtest
2022-06-17T15:02:55-6c25ba6/windows-386-2012
2022-06-17T15:02:55-6c25ba6/windows-arm64-10
2022-06-17T15:02:55-6c25ba6/windows-arm64-11
2022-06-16T21:58:40-9068c68/windows-386-2012
2022-06-16T21:25:35-7bad615/freebsd-arm-paulzhol
2022-06-16T21:25:35-7bad615/windows-arm64-11

(CC @golang/runtime)

[bcmills]

(Marking as release-blocker because the failure mode is new and frequent, and linux/386 and windows/386 are first-class ports.)

[mknyszek]

I give up. I will make this a benchmark. I no longer believe there's a way to make this test not flaky without running many, many more iterations.

[gopherbot]

Change https://go.dev/cl/412878 mentions this issue: runtime: convert flaky semaphore linearity test into benchmark