First, the width was not being correctly defined for non-vector
instructions.

Second, the order of the width/condition was incorrect when the
instruction was prefixed with a V. That is, for V prefixed instructions,
the order is predicate/width while for non-V prefixed instructions the
order is width/predicate.

Also fixes bug in target lowering that did not always convert results
of a compare to i1.

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

Review URL: https://codereview.chromium.org/1415953007 .