runtime:cpu4: TestUsingVDSO failures

#!watchflakes
default <- pkg == "runtime:cpu4" && test == "TestUsingVDSO"

Issue created automatically to collect these failures.

Example (log):

=== RUN   TestUsingVDSO
=== PAUSE TestUsingVDSO
=== CONT  TestUsingVDSO
    vdso_test.go:51: GO_WANT_HELPER_PROCESS=1 /bin/strace -f -e clock_gettime /home/swarming/.swarming/w/ir/x/t/go-build3885972143/b001/runtime.test -test.run=^TestUsingVDSO$
    vdso_test.go:57: /bin/strace: Process 140051 attached
        /bin/strace: Process 140052 attached
        /bin/strace: Process 140050 attached
        /bin/strace: Process 140053 attached
        [pid 140050] ???( <unfinished ...>
        [pid 140049] --- stopped by SIGURG ---
        /bin/strace: ptrace(PTRACE_LISTEN,pid:140049,sig:0): Input/output error
        /bin/strace: Process 140049 detached
        /bin/strace: Process 140051 detached
        /bin/strace: Process 140052 detached
        /bin/strace: Process 140050 detached
        /bin/strace: Process 140053 detached
    vdso_test.go:70: exit status 1
--- FAIL: TestUsingVDSO (0.14s)

— watchflakes