TSC's helpers cause module to be marked as CommonJS

[devongovett]

TSC builds helpers that look like this:

var __classPrivateFieldSet = (this && this.__classPrivateFieldSet) || ...

The this reference there causes Parcel to mark the module as CommonJS. This in turn causes the packager to add a setter to the $parcel$export call, which may include invalid syntax (e.g. function (v) { return (parcelRequire("3RBLs")) = v; }).

parcel/packages/packagers/js/src/ScopeHoistingPackager.js

Lines 1030 to 1032 in 3678a9f

	let set = asset.meta.hasCJSExports
	? ', ' + this.buildFunctionExpression(['v'], `${resolved} = v`)
	: '';

These are potentially two separate issues:

1. We should detect that the this reference is only a read, not a write to avoid marking as CJS.
2. We should detect that the resolved export is a parcelRequire and not add a setter in that case?

[devongovett]

Filed a TSC issue: microsoft/TypeScript#50761

[devongovett]

Fixed by #9318 #9330