The gap is chosen unneccessarily large, leading to too early growing of
the assembler buffer.

R=mstarzinger@chromium.org

Change-Id: I9ddbe1d59929f2a76511cbc2d18c054fb8eafa74
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1914213Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64939}