Fix prettier test compat with Babel 8

[nicolo-ribaudo]

Q	A
Fixed Issues?
Patch: Bug Fix?
Major: Breaking Change?
Minor: New Feature?
Tests Added + Pass?	Yes
Documentation PR Link
Any Dependency Changes?
License	MIT

This tests contains invalid JSX that is disallowed in Babel 8. https://github.com/prettier/prettier/blob/main/tests/format/typescript/optional-variance/with-jsx.tsx

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/52067/

[nicolo-ribaudo]

This fixes the E2E breaking prettier test. The remaining failures are fixed by #14592.

cc @sosukesuzuki I would love your review, since you know how prettier tests work! Also, I wonder if prettier could format > in JSX as {">"}, since > is technically invalid.

[liuxingbaoyu]

Is this a temporary fix?
This test also exists in our repo, just with babel8 disabled.

[nicolo-ribaudo]

No, this is not temporary! JSX text cannot contain >, but we are disallowing it only in Babel 8 to avoid breaking changes. JSX has a test where it uses > in JSX, so it doesn't work with Babel 8: this PR updates that test to make it valid.

[nicolo-ribaudo]

#12451

[liuxingbaoyu]

The only change is that I made the error recoverable (just by deleting throw in front of this.raise).

babel/packages/babel-parser/src/plugins/typescript/index.js

Lines 3200 to 3218 in e8c4b78

	parseMaybeAssign(...args): N.Expression {
	// Note: When the JSX plugin is on, type assertions (`<T> x`) aren't valid syntax.
	let state: ?State;
	let jsx;
	let typeCast;
	if (
	this.hasPlugin("jsx") &&
	(this.match(tt.jsxTagStart) || this.match(tt.lt))
	) {
	// Prefer to parse JSX if possible. But may be an arrow fn.
	state = this.state.clone();
	jsx = this.tryParse(() => super.parseMaybeAssign(...args), state);
	/*:: invariant(!jsx.aborted) */
	/*:: invariant(jsx.node != null) */
	if (!jsx.error) return jsx.node;

It seems we can modify this to make it recoverable.
Instead of the current behavior SyntaxError: Unexpected token.

[nicolo-ribaudo]

I opened #14616 to make it recoverable, which is way better. Thanks! 😄