Use __NR_exit_group in MinidumpWriterTest.MinidumpStacksSkippedIfRequested.

Also adds waits for all child processes spawned in MinidumpWriterTest.

Bug: 725754
Change-Id: I3248925993dede2c113ab1989b322a9d9c8f24bd
Reviewed-on: https://chromium-review.googlesource.com/513480
Reviewed-by: Mark Mentovai <mark@chromium.org>
Cr-Mirrored-From: https://chromium.googlesource.com/breakpad/breakpad
Cr-Mirrored-Commit: 16f5b5f5125d4f77a67fc70a0ac09da5e4761bcc
1 file changed