Support providing and retrieving WebAssembly.Memory

[justjake]

• Fixes How to access wasm module's Memory? #146 by adding wasmMemory: WebAssembly.Memory option for newVariant, and mod.getWasmMemory() method for QuickJS[Async]WASMModule
• Fixes Async Regression "TypeError: Object not disposable" in v0.26.0 #138 by
  • removing internal use of using statement
  • Use ESBuild Symbol.for('Symbol.dispose') if Symbol.dispose isn't defined globally.