Move browser tests that require installation into their own files.

test/utils.dart

Index: test/utils.dart
diff --git a/test/utils.dart b/test/utils.dart
index 166b7ba868fd165cab37d2f16de2ea72ba9ecde2..0b2f3a2aef37df7944a6f81ae5d082a24d907c7a 100644
--- a/test/utils.dart
+++ b/test/utils.dart
@@ -227,7 +227,7 @@ LiveTest createTest(body()) {
 /// Runs [body] as a test.
 ///
 /// Once it completes, returns the [LiveTest] used to run it.
-Future<LiveTest> runTest(body()) {
+Future<LiveTest> runTestBody(body()) {
   var liveTest = createTest(body);
   return liveTest.run().then((_) => liveTest);
 }