ULSJsonMessageLoaderTest: Expect a generic Exception

This allows to change from MWException to
Wikimedia\Assert\ParameterTypeException by
I8287118cf8ec01326ead9c90a38f7b4134c3eba9.

Change-Id: Ib0cb388958cf720052ca6df73d5145b7ab3f9529

tests/phpunit/ULSJsonMessageLoaderTest.php

@@ -16,14 +16,14 @@ class ULSJsonMessageLoaderTest extends \PHPUnit\Framework\TestCase {
 	public function testGetFilenamesWithBadInput() {
 		$instance = new ULSJsonMessageLoader();
 
-		$this->setExpectedException( \MWException::class );
+		$this->setExpectedException( \Exception::class );
 		$instance->getFilenames( null );
 	}
 
 	public function testGetMessagesWithBadInput() {
 		$instance = new ULSJsonMessageLoader();
 
-		$this->setExpectedException( \MWException::class );
+		$this->setExpectedException( \Exception::class );
 		$instance->getMessages( null );
 	}