These are added as mjsunit tests for now since they haven't been merged
to the spec repo. When that happens, the wasm-spec-tests testsuite can
be updated to include these tests, and the tests in this directory can
be removed.

This CL also adds the test/mjsunit/wasm/bulk-memory-spec directory to a
list of directories that aren't checked for copyright (since these files
are auto-generated).

Bug: v8:7747
Change-Id: I906f2ca45f497a6728f94afb9b3330971e1d3fd5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1600363
Commit-Queue: Ben Smith <binji@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61395}