Port cd34523b

Original Commit Message:

    With this CL we add proposal tests to the wasm-spec-tests. For this I
    extended the update-wasm-spec-tests.sh script. Additionally to
    generating the spec tests it does the following:

    For each proposal it identifies those tests that are different to the
    spec tests, and then copies those tests also to the wasm-spec-tests
    directory.

    Additionally I adjusted the test runner of the wasm spec test to
    run the proposal tests with the correct flags.

R=ahaas@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=
LOG=N

Change-Id: Ia976d8017cacb61b46fe076c39ade6bc6137b7e9
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1708989Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#62853}