Forge (Google3) can only run 64-bit executables. As Torque runs as part
of the build process, we need a 32-bit "cross-compile" mode when
we target 32-bit architectures. Note that this flag won't be needed
in Chromium/V8 land, since we build V8 with the same bit width as
the target architecture.

This CL adds a new runtime flag to torque "-m32". When enabled, the
flag forces 32-bit word sizes for various pointer/word sizes. By
default, the host system sizes from {src/commons/globals.h}
are used.

R=tebbi@chromium.org

Bug: v8:9641
Change-Id: I8701eec45e3fb59dc65049b0a679d34589c4127f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1763540
Commit-Queue: Simon Zünd <szuend@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#63334}