Changes calls to conversion builtins in Wasm wrappers to use the builtin
address directly rather than going via the Code object which results in
the trampoline being unnecessarily executed.

Bug: v8:9338
Change-Id: I74593dbda3c8bd308be65bc98ce85213a98f78b5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1648274Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62094}