x/tools/internal/robustio: TestFileID consistently failing on android builders with EPERM

[bcmills]

#!watchflakes
post <- builder ~ `^android-.*` && test == "TestFileID"

https://build.golang.org/log/2986bd93a11934517802df1e2b7314280acfd478:

--- FAIL: TestFileID (0.00s)
    robustio_test.go:63: link /data/local/tmp/go_android_exec/robustio.test-16829/TestFileID3286931938/002/real /data/local/tmp/go_android_exec/robustio.test-16829/TestFileID3286931938/005/hardlink: permission denied
FAIL
exitcode=1
FAIL	golang.org/x/tools/internal/robustio	2.577s

[bcmills]

The test seems to be assuming that it can create hard-links in t.TempDir():
https://cs.opensource.google/go/x/tools/+/master:internal/robustio/robustio_test.go;l=62;drc=3856a5d80cf9ed9505c189333d753350aaaffcd2

While that is usually true, it does not hold for all filesystems and container implementations.
(Compare https://pkg.go.dev/internal/testenv#HasLink.)

[gopherbot]

Change https://go.dev/cl/462415 mentions this issue: internal/robustio: skip os.Link test on android