Changes:
- Add --experimental-wasm-gc-experiments flag.
- Add array.copy opcode. Implement it in decoding and code generation
  behind the new flag.
- Add WasmCodeBuilder::BoundsCheckArrayCopy. Move BoundsCheckArray to
  the private section.
- Add WasmArrayCopy and WasmArrayCopyWithChecks builtin.
- Add WasmArrayCopy runtime function.
- Add WasmArray::ElementSlot.
- Always print two hex digits in CHECK_PROTOTYPE_OPCODE.
- In test-gc, print the thrown-error message if the function should not
  throw.
- In test-gc, add GetResultObject with one argument.

Bug: v8:7748
Change-Id: I58f4d37e254154596cdef5e78482b55260dd3782
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2912729
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74806}