[fuchsia] Add zx_vmo_replace_as_executable to tests
[fuchsia] Add zx_vmo_replace_as_executable to tests

Fuchsia in the future will create VMOs as non-executable (i.e.,
without ZX_RIGHT_EXECUTE) by default, so this necessary preparation
for that.

Change-Id: I00ada804d1d16db4f50ff3882058e382b1845328
Reviewed-on: https://chromium-review.googlesource.com/c/1419778
Reviewed-by: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>
Commit-Queue: Matthew Dempsky <e56ac2c500064424afac424d4b5e53bd0570a731@chromium.org>

chromium/crashpad,chromium/crashpad,chromium/crashpad