tracer_test.go is flaky (and hard to reproduce)

[10000TB]

Describe the bug
tracer_test.go would fail opportunistically across a larger number of successful runs.

To Reproduce
Steps to reproduce the behavior:

Run the test via go test, but I haven't be able to reproduce it. The flaky run came from our automated continuous runs, that run every hour.

Expected behavior

Test pass w/o offending changes.

Additional context

ok  	github.com/u-root/u-root/pkg/spidev	0.011s	coverage: 91.4% of statements
coverage: 40.4% of statements
panic: test timed out after 10m0s

goroutine 37 [running]:
testing.(*M).startAlarm.func1()
	/usr/local/go/src/testing/testing.go:2029 +0x8e
created by time.goFunc
	/usr/local/go/src/time/sleep.go:176 +0x32

goroutine 1 [chan receive]:
testing.(*T).Run(0xc00011b1e0, {0x575e6c?, 0x4c6625?}, 0x5806d8)
	/usr/local/go/src/testing/testing.go:1487 +0x37a
testing.runTests.func1(0xc00011b1e0?)
	/usr/local/go/src/testing/testing.go:1839 +0x6e
testing.tRunner(0xc00011b1e0, 0xc0000fdca0)
	/usr/local/go/src/testing/testing.go:1439 +0x102
testing.runTests(0xc0000babe0?, {0x6895c0, 0x6, 0x6}, {0x7fc114c815b8?, 0x40?, 0x68f0a0?})
	/usr/local/go/src/testing/testing.go:1837 +0x457
testing.(*M).Run(0xc0000babe0)
	/usr/local/go/src/testing/testing.go:1719 +0x5d9
main.main()
	_testmain.go:121 +0x255

goroutine 34 [chan receive]:
github.com/u-root/u-root/pkg/strace.runAndCollectTrace(0xc0001ba000, 0xc0001cc000)
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer_test.go:58 +0x1db
github.com/u-root/u-root/pkg/strace.TestMultiProcess(0x0?)
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer_test.go:89 +0x92
testing.tRunner(0xc0001ba000, 0x5806d8)
	/usr/local/go/src/testing/testing.go:1439 +0x102
created by testing.(*T).Run
	/usr/local/go/src/testing/testing.go:1486 +0x35f

goroutine 35 [syscall, locked to thread]:
syscall.Syscall6(0x3d, 0xffffffffffffffff, 0xc0000ddccc, 0x0, 0x0, 0x0, 0x0)
	/usr/local/go/src/syscall/asm_linux_amd64.s:43 +0x5
golang.org/x/sys/unix.wait4(0x546460?, 0xc000184af0?, 0x8?, 0xc0000ddd08?)
	/src/golang/src/golang.org/x/sys/unix/zsyscall_linux.go:224 +0x4e
golang.org/x/sys/unix.Wait4(0x1?, 0xc0000ddd04, 0xc0000ddfc0?, 0xc0000ddeb0?)
	/src/golang/src/golang.org/x/sys/unix/syscall_linux.go:362 +0x2b
github.com/u-root/u-root/pkg/strace.wait(0x54db40?)
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer.go:31 +0x3a
github.com/u-root/u-root/pkg/strace.(*tracer).runLoop(0xc0000dde40)
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer.go:301 +0x5a
github.com/u-root/u-root/pkg/strace.Trace(0x7fc0ec659198?, {0xc0001d4fc0, 0x2, 0x2})
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer.go:240 +0x526
github.com/u-root/u-root/pkg/strace.runAndCollectTrace.func1()
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer_test.go:53 +0xae
created by github.com/u-root/u-root/pkg/strace.runAndCollectTrace
	/src/golang/src/github.com/u-root/u-root/pkg/strace/tracer_test.go:52 +0x19d

goroutine 36 [IO wait]:
internal/poll.runtime_pollWait(0x7fc0ec6590a8, 0x72)
	/usr/local/go/src/runtime/netpoll.go:302 +0x89
internal/poll.(*pollDesc).wait(0xc0001c4120?, 0xc000160007?, 0x1)
	/usr/local/go/src/internal/poll/fd_poll_runtime.go:83 +0x32
internal/poll.(*pollDesc).waitRead(...)
	/usr/local/go/src/internal/poll/fd_poll_runtime.go:88
internal/poll.(*FD).Read(0xc0001c4120, {0xc000160007, 0x5f9, 0x5f9})
	/usr/local/go/src/internal/poll/fd_unix.go:167 +0x25a
os.(*File).read(...)
	/usr/local/go/src/os/file_posix.go:31
os.(*File).Read(0xc0001aa018, {0xc000160007?, 0x65cfa0?, 0xc0001c06a0?})
	/usr/local/go/src/os/file.go:119 +0x5e
bytes.(*Buffer).ReadFrom(0xc00018e2a0, {0x5b7da0, 0xc0001aa018})
	/usr/local/go/src/bytes/buffer.go:204 +0x98
io.copyBuffer({0x5b7be0, 0xc00018e2a0}, {0x5b7da0, 0xc0001aa018}, {0x0, 0x0, 0x0})
	/usr/local/go/src/io/io.go:412 +0x14b
io.Copy(...)
	/usr/local/go/src/io/io.go:385
os/exec.(*Cmd).writerDescriptor.func1()
	/usr/local/go/src/os/exec/exec.go:311 +0x3a
os/exec.(*Cmd).Start.func1(0xc0001c07a0?)
	/usr/local/go/src/os/exec/exec.go:448 +0x25
created by os/exec.(*Cmd).Start
	/usr/local/go/src/os/exec/exec.go:447 +0x785
FAIL	github.com/u-root/u-root/pkg/strace	600.009s
ok  	github.com/u-root/u-root/pkg/strace/internal/abi	0.002s	coverage: 41.3% of statements
ok  	github.com/u-root/u-root/pkg/strace/internal/binary	0.002s	coverage: 0.0% of statements
ok  	github.com/u-root/u-root/pkg/syscallfilter	0.014s	coverage: 88.5% of statements

[10000TB]

Haven't been able to produce it manually. But I am pretty certain it happens once in every while.