Replace and remove JavaException(s).

pkg/analyzer/test/generated/source_factory_test.dart

Index: pkg/analyzer/test/generated/source_factory_test.dart
diff --git a/pkg/analyzer/test/generated/source_factory_test.dart b/pkg/analyzer/test/generated/source_factory_test.dart
index 77f9d740270368f40125fcb66023ab738c4ae1a9..c8eb8f2d969be80aeed50f73d6f513323c30f1b2 100644
--- a/pkg/analyzer/test/generated/source_factory_test.dart
+++ b/pkg/analyzer/test/generated/source_factory_test.dart
@@ -239,14 +239,13 @@ class SourceFactoryTest {
 
   void test_fromEncoding_invalidUri() {
     SourceFactory factory = new SourceFactory([]);
-    expect(() => factory.fromEncoding("<:&%>"),
-        throwsA(new isInstanceOf<IllegalArgumentException>()));
+    expect(() => factory.fromEncoding("<:&%>"), throwsArgumentError);
   }
 
   void test_fromEncoding_noResolver() {
     SourceFactory factory = new SourceFactory([]);
     expect(() => factory.fromEncoding("foo:/does/not/exist.dart"),
-        throwsA(new isInstanceOf<IllegalArgumentException>()));
+        throwsArgumentError);
   }
 
   void test_fromEncoding_valid() {