Add support for client/dartc compilation only tests.

tools/testing/dart/test_options.dart

Index: tools/testing/dart/test_options.dart
diff --git a/tools/testing/dart/test_options.dart b/tools/testing/dart/test_options.dart
index 5b7acdf5e392a1887b7e3d7bcc97895b94756aa6..d75ee537fdbc4003110c1d633527421a96e70988 100644
--- a/tools/testing/dart/test_options.dart
+++ b/tools/testing/dart/test_options.dart
@@ -248,9 +248,11 @@ class TestOptionsParser {
         if (slashLocation != -1) {
           suite = pattern.substring(0, slashLocation);
           pattern = pattern.substring(slashLocation + 1);
+          pattern = pattern.replaceAll('*', '.*');
+          pattern = pattern.replaceAll('/', '.*');
+        } else {
+          pattern = ".*";
         }
-        pattern = pattern.replaceAll('*', '.*');
-        pattern = pattern.replaceAll('/', '.*');
         if (selectorMap.containsKey(suite)) {
           print("Warning: selector '$suite/$pattern' overrides " +
                 "previous selector for suite '$suite'");