Per-closure breakpoints; restructure breakpoint implementation to keep a list of conditions.

runtime/observatory/tests/service/test_helper.dart

Index: runtime/observatory/tests/service/test_helper.dart
diff --git a/runtime/observatory/tests/service/test_helper.dart b/runtime/observatory/tests/service/test_helper.dart
index 6da69becfc01f52b5f273e55768acc87ae72a345..fed6ee1c609f27016a11ab13f2b4920fb407a5e0 100644
--- a/runtime/observatory/tests/service/test_helper.dart
+++ b/runtime/observatory/tests/service/test_helper.dart
@@ -108,6 +108,9 @@ void runIsolateTests(List<String> mainArgs,
   } else {
     var process = new _TestLauncher();
     process.launch(pause_on_exit).then((port) {
+      if (mainArgs.contains("--gdb")) {
+        port = 8181;
+      }
       String addr = 'ws://localhost:$port/ws';
       var testIndex = 1;
       var totalTests = tests.length;
@@ -192,6 +195,9 @@ Future runVMTests(List<String> mainArgs,
   } else {
     var process = new _TestLauncher();
     process.launch(pause_on_exit).then((port) async {
+      if (mainArgs.contains("--gdb")) {
+        port = 8181;
+      }
       String addr = 'ws://localhost:$port/ws';
       var testIndex = 1;
       var totalTests = tests.length;