parser: `ModuleKind::Unambiguous` does not allow Top-level await

[sapphi-red]

await new Promise(resolve => {}) cannot be parsed with ModuleKind::Unambiguous.
This is allowed by babel.

Babel REPL (strict is enabled, so that means it's parsing in module mode)

Related code:

oxc/crates/oxc_parser/src/lib.rs

Lines 481 to 487 in ecdda9e

	if source_type.is_unambiguous() {
	program.source_type = if module_record.has_module_syntax {
	source_type.with_module(true)
	} else {
	source_type.with_script(true)
	};
	}

(we may need to add a separate flag for TLA as whether TLA is a module syntax can be controversial)

tsc has some logic to reparse https://github.com/microsoft/TypeScript/blob/efca03ffed10dccede4fbc8dd8a624374e5424d9/src/compiler/parser.ts#L1862
#15494 (review)

[Boshen]

Previously:

• top level await unambiguous source type problem backlog#149