Don't show terminal in test

Seems to be causing a Chromium error in containers related to gpu

extensions/vscode-api-tests/src/singlefolder-tests/terminal.test.ts

@@ -79,7 +79,6 @@ import { doesNotThrow, equal, ok, deepEqual, throws } from 'assert';
 					TEST: '`'
 				}
 			});
-			terminal.show();
 			doesNotThrow(() => {
 				// Print an environment variable value so the echo statement doesn't get matched
 				if (process.platform === 'win32') {