If we underestimate the size of the assembler buffer when compiling
directly on the GC heap, we fallback to off-heap compilation and
the Code object is incomplete in the memory.

We know a Code object is incomplete when its relocation_info is
undefined.

Bug: v8:11872
Change-Id: I282fd442e0bf227d9d2cca5a47b3139030f5d64e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3013937
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75634}