Adds a test for the draft JS API spec from this PR:

  WebAssembly/gc#352

This primarily tests the internal object methods described in the spec.
It doesn't yet test the ToWebAssemblyValue / ToJSValue conversions.

Also syncs a portion of the module builder code with V8 to allow
constructing a subset of GC-using modules.

  * Update opcodes to final versions in MVP document
  * Undid strict/non-strict behavior difference

  * The exported-object test should run on V8 now
  * Non-GC JS API tests should run correctly too

[test] Add tentative JS API tests for Exported GC Object

Rename extern.in/externalize

[spec] Extend definition of constants

[spec] A few fixes

Add missing init expression to table text format

…ebAssembly#1662)

…bAssembly#1659)

…#1668)

depended → dependent

…ariable

…ssembly#1680)

…ebAssembly#1682)

Check that the condition must be a sequence of folded (as opposed to unfolded)
instructions, but also check that having zero or multiple folded instructions is
allowed.

)

The interpreter Makefile captures the output of cding into the unittest
directory and listing the unittest files it contains. Under some circumstances,
the `cd` command will print the new current directory, and that output was
incorrectly being interpreted as the path to a unittest, causing the build to
fail.

Fix this problem by redirecting the output of cd, if any, to /dev/null.

Fixes WebAssembly#1681.

…bly#1666)

Change the interpreter implementation of backward copying in the evaluation of
memory.copy and table.copy to match the implementation given in the spec. This
does not change any behavior.

…act operation

This became unused in WebAssembly#745.

Also updates wasm-module-builder for necessary changes, such as support for
global init expressions with GC operations. These changes are imported from the
upstream V8 file. This module builder change also requires changes in a few
other test files that used the old init API.

[test] Add JS API tests for I31 refs

Mostly tests the ToWebAssemblyValue metafunction

[test] Add boundary cast tests for ToWebAssemblyValue

in Appendix page.

Signed-off-by: YiYing He <[email protected]>