Drive-by cleanup: IWYU for macro-assembler-ia32.cc.

IWYU added src/heap/basic-memory-chunk.h which failed a presubmit, so I
updated src/DEPS to allow for including it.

Bug: v8:11217,v8:7490
Change-Id: I63662bfb2b34e354e94f6052edfcb92f1341da58
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2583675Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71729}