Make sure we delete new TS internal file names too (#230011)

https://github.com/microsoft/TypeScript/pull/59720

extensions/postinstall.mjs

@@ -26,7 +26,10 @@ function processRoot() {
 function processLib() {
 	const toDelete = new Set([
 		'tsc.js',
+		'_tsc.js',
+
 		'typescriptServices.js',
+		'_typescriptServices.js',
 	]);
 
 	const libRoot = path.join(root, 'lib');