Porting: 138d2dfc

Original comment:
   This allows immediates to be encoded directly into instructions, rather than
   mov-ing constants to registers first.

   This patch only changes emit_{i64,i32}_add, other emit_ functions will be changed once
   this approach has been approved.

Change-Id: I8442642126555f47a47d511f0ca9d4c00ed82da1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1546050
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Junliang Yan <jyan@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#60533}