Skylark: Fix an infinite loop in the parser

--
MOS_MIGRATED_REVID=88830705
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java b/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
index 3981d0c..51da72c 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/ParserTest.java
@@ -846,6 +846,13 @@
   }
 
   @Test
+  public void testLoadNoSymbol() throws Exception {
+    syntaxEvents.setFailFast(false);
+    parseFileForSkylark("load('/foo/bar/file')\n");
+    syntaxEvents.assertContainsEvent("syntax error");
+  }
+
+  @Test
   public void testLoadOneSymbol() throws Exception {
     List<Statement> statements = parseFileForSkylark(
         "load('/foo/bar/file', 'fun_test')\n");