WebAssembly JS API: export a module namespace object instead of a module environment

WebAssembly JS API: export a module namespace object instead of a module environment
https://bugs.webkit.org/show_bug.cgi?id=165121

Reviewed by Saam Barati.

This patch setup AbstractModuleRecord further for WebAssemblyModuleRecord.
For exported entries in a wasm instance, we set up exported entries for
AbstractModuleRecord. This allows us to export WASM exported functions in
the module handling code.

Since the exported entries in the abstract module record are correctly
instantiated, the module namespace object for WASM module also starts
working correctly. So we start exposing the module namespace object
as `instance.exports` instead of the module environment object.

And we move SourceCode, lexicalVariables, and declaredVariables fields to
JSModuleRecord since they are related to JS source code (in the spec words,
they are related to the source text module record).

* runtime/AbstractModuleRecord.cpp:
(JSC::AbstractModuleRecord::AbstractModuleRecord):
* runtime/AbstractModuleRecord.h:
(JSC::AbstractModuleRecord::sourceCode): Deleted.
(JSC::AbstractModuleRecord::declaredVariables): Deleted.
(JSC::AbstractModuleRecord::lexicalVariables): Deleted.
* runtime/JSModuleRecord.cpp:
(JSC::JSModuleRecord::JSModuleRecord):
* runtime/JSModuleRecord.h:
(JSC::JSModuleRecord::sourceCode):
(JSC::JSModuleRecord::declaredVariables):
(JSC::JSModuleRecord::lexicalVariables):
* wasm/WasmFormat.cpp:
* wasm/js/JSWebAssemblyInstance.cpp:
(JSC::JSWebAssemblyInstance::finishCreation):
* wasm/js/WebAssemblyFunction.cpp:
* wasm/js/WebAssemblyInstanceConstructor.cpp:
(JSC::constructJSWebAssemblyInstance):
* wasm/js/WebAssemblyModuleRecord.cpp:
(JSC::WebAssemblyModuleRecord::create):
(JSC::WebAssemblyModuleRecord::WebAssemblyModuleRecord):
(JSC::WebAssemblyModuleRecord::finishCreation):
WebAssemblyModuleRecord::link should perform linking things.
So allocating exported entries should be done here.
(JSC::WebAssemblyModuleRecord::link):
* wasm/js/WebAssemblyModuleRecord.h:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@209171 268f45cc-cd09-0410-ab3c-d52691b4dbfc