With this CL, externref parameters are supported by the generic wrapper.
Externref parameters get handled in a separate loop which runs after the
loop which converts primitive type parameters from JavaScript values to
WebAssembly values. Externref parameters get handled separately because
the conversion of primitive type parameters may cause a GC, and it would
be hard for the GC to identify stack slots which contain reference
parameters which have already been processed.

As an optimization we remember in the first loop if we have seen a
reference parameter. For functions without a reference parameter we
would not iterate the parameters for a second time.

R=thibaudm@chromium.org

Bug: v8:12565
Change-Id: Ib36bee9d8e6b1606250fcd5f2e9cdbbdfed96356
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3412079Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78814}