Ensure that llvm-mc parses unit tests in x86-32 mode.

Add -arch=x86 and -filetype=obj to all RUN lines involving
llvm-mc.

This fixes the failing validation of callindirect.pnacl.ll.

The following tests fail to validate (some due to the
addition of -filetype=obj):
 * convert.ll
 * globalinit.pnacl.ll
 * mangle.ll
 * nacl-atomic-fence-all.ll
 * shift.ll

BUG=none
R=stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=d9ea7ad

[Jim Stichnoth, 2014-07-23 00:07:25]

LGTM.

If you want to be absolutely true to the way llvm-mc is run, also add
-filetype=obj to the command lines.

[wala, 2014-07-23 01:22:01]

On 2014/07/23 00:07:25, stichnot wrote:
> LGTM.
> 
> If you want to be absolutely true to the way llvm-mc is run, also add
> -filetype=obj to the command lines.

Done. Adding -filetype=obj caused some tests to fail to validate due to issues
with object file emission. The tests are:
 * convert.ll 
 * globalinit.pnacl.ll  
 * nacl-atomic-fence-all.ll 
 * shift.ll

[wala, 2014-07-23 01:26:09]

Committed patchset #3 manually as rd9ea7ad (presubmit successful).