Subzero: Work around another llvm-mc parser bug for relocatable symbols.

Subzero: Work around another llvm-mc parser bug for relocatable symbols.

There's already a hack that emits asm like:
  lea eax, myglobal
instead of:
  mov eax, [myglobal]
because of an llvm-mc parser bug.  However, the lea hack still doesn't work if the symbol is a reserved word, e.g.:
  lea eax, flags

The extra hack is to drop into AT&T syntax temporarily:
.att_syntax
  leal flags, %eax
.intel_syntax

BUG= none
R=jvoung@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=523ef72

[Jim Stichnoth, 2014-09-04 18:08:17]

stichnot@chromium.org changed reviewers:
+ jvoung@chromium.org

[jvoung (off chromium), 2014-09-04 18:22:49]

LGTM

[Jim Stichnoth, 2014-09-04 18:32:23]

Committed patchset #1 (id:1) manually as 523ef72 (presubmit successful).