Fixes typo in NegativeParserTest and updates test to check for warnings

compiler/javatests/com/google/dart/compiler/CompilerTestCase.java

Index: compiler/javatests/com/google/dart/compiler/CompilerTestCase.java
diff --git a/compiler/javatests/com/google/dart/compiler/CompilerTestCase.java b/compiler/javatests/com/google/dart/compiler/CompilerTestCase.java
index f7dfe4b495c3cc142d8eeafd776316e69b9bd059..ca89628071d860791c0c1acab323b799acefdf7f 100644
--- a/compiler/javatests/com/google/dart/compiler/CompilerTestCase.java
+++ b/compiler/javatests/com/google/dart/compiler/CompilerTestCase.java
@@ -4,6 +4,8 @@
 
 package com.google.dart.compiler;
 
+import static com.google.dart.compiler.common.ErrorExpectation.assertErrors;
+
 import com.google.common.collect.Lists;
 import com.google.dart.compiler.CommandLineOptions.CompilerOptions;
 import com.google.dart.compiler.ast.DartInvocation;
@@ -13,7 +15,6 @@ import com.google.dart.compiler.ast.DartNodeTraverser;
 import com.google.dart.compiler.ast.DartUnit;
 import com.google.dart.compiler.ast.LibraryUnit;
 import com.google.dart.compiler.common.ErrorExpectation;
-import static com.google.dart.compiler.common.ErrorExpectation.assertErrors;
 import com.google.dart.compiler.parser.DartParser;
 import com.google.dart.compiler.parser.DartParserRunner;
 import com.google.dart.compiler.parser.DartScannerParserContext;
@@ -306,6 +307,14 @@ public abstract class CompilerTestCase extends TestCase {
   }
 
   /**
+   * Parses given source and checks parsing problems.
+   */
+  protected final void parseExpectWarnings(String code, ErrorExpectation... expectedWarnings) {
+    DartParserRunner runner =  DartParserRunner.parse(getName(), code, Integer.MAX_VALUE, true);
+    List<DartCompilationError> errors = runner.getErrors();
+    assertErrors(errors, expectedWarnings);
+  }
+  /**
    * @return the {@link DartInvocation} with given source. This is inaccurate approach, but good
    *         enough for specific tests.
    */