It turns out that there are several instruction in the ARM integrated
assembler that do not get translated correctly. This results in the
spec2k tests not being compilable.

To workaround this problem, this CL adds a (temporary) flag that allows all translations to be applied by the integrated assembler. When this flag is false (the default) only correctly working translations to be applied by the integrated assembler. This allows lit tests to still be applied to the correct portions of broken translations.

This CL also fixes a bug with local (instruction) labels that did not
generate a corresponding label to the -filetype=iasm assembly file.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4334
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/1424923005 .