Update tests to use FileCheck instead of grep (which is deprecated in the LLVM regression suite)

Update tests to use FileCheck instead of grep (which is deprecated in the LLVM regression suite)

BUG=None
R=mseaborn@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-llvm.git;a=commit;h=c5d1983

[eliben, 2013-05-14 21:49:24]

Hi Mark,

Usage of grep is deprecated for LLVM regression tests and FileCheck has to be
used instead; grep support may be removed in the future when all the upstream
tests get rewritten to use FileCheck (the process is underway). Usage of
FileCheck also helps reduce the amount of total tool runs.

PTAL

[Mark Seaborn, 2013-05-14 22:05:45]

LGTM

[eliben, 2013-05-14 22:07:57]

Committed patchset #1 manually as rc5d1983 (presubmit successful).