On ia32, we can encode the address of the stack limit in the operand
directly, saving one mov instruction and reducing register pressure.

R=titzer@chromium.org

Bug: v8:6600
Change-Id: I2742efbfea16d56d648c233a2dba1d8672dc489d
Reviewed-on: https://chromium-review.googlesource.com/930961
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51463}