runtime: timeouts on netbsd-arm64-bsiegert builder

[bcmills]

#!watchflakes
post <- pkg == "runtime" && builder ~ `netbsd-arm.*-bsiegert` && (log ~ `SIGQUIT` || log ~ `test timed out` || `failed to start: context deadline exceeded` ||  `panic: finalizer started .* ago .*, but did not return`)

(attn @bsiegert @golang/netbsd; CC @golang/runtime)

Pulled out from #57636 and others.

[gopherbot]

Found new dashboard test flakes for:

#!watchflakes
post <- pkg == "runtime" && builder ~ `netbsd-arm.*-bsiegert` && (`SIGQUIT` || `test timed out` || `failed to start: context deadline exceeded` ||  `panic: finalizer started .* ago .*, but did not return`)

2022-12-16 03:40 netbsd-arm64-bsiegert go@24ac659a runtime.TestCgoExecSignalMask (log)

--- FAIL: TestCgoExecSignalMask (0.18s)
    exec.go:146: test timed out while running command: /var/gobuilder/buildlet/tmp/go-build2870843524/testprogcgo.exe CgoExecSignalMask
    crash_test.go:58: /var/gobuilder/buildlet/tmp/go-build2870843524/testprogcgo.exe CgoExecSignalMask: exit status 2
    crash_cgo_test.go:140: expected "OK\n", got SIGQUIT: quit
        PC=0x20018aefc m=8 sigcode=0

        r0      0x1
        r1      0xef4
        r2      0x4000217dbc
        r3      0x10020
...
        r24     0xffffd2779000
        r25     0xfffffb85b000
        r26     0x4000217e48
        r27     0x1
        r28     0x4000082b60
        r29     0x4000217d48
        lr      0x20018aee0
        sp      0x4000217d50
        pc      0x20018aefc
        fault   0x24f2

— watchflakes