This adds a test checking whether function identity is preserved upon
re-export of various function kinds. The tests are expected to all pass
and just increase code coverage.

R=ahaas@chromium.org
TEST=mjsunit/wasm/export-identity

Change-Id: I4fbb7db2d78c7ffeb6278d6b6d87a7c029326387
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1687893Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62516}