Mark dwarf_stack_trace_test as flaky in product mode, due to identical code folding.

tests/standalone/dwarf_stack_trace_test.dart

Index: tests/standalone/dwarf_stack_trace_test.dart
diff --git a/tests/standalone/dwarf_stack_trace_test.dart b/tests/standalone/dwarf_stack_trace_test.dart
index f5ec20b37b7b19fd19068aa40206023aa41d534d..117768b24cdeef767d411ae163a1a648cfef9548 100644
--- a/tests/standalone/dwarf_stack_trace_test.dart
+++ b/tests/standalone/dwarf_stack_trace_test.dart
@@ -71,7 +71,7 @@ main() {
     return;
   }
 
-  var frameRegex = new RegExp("pc ([0-9a-z]+)  ([0-9a-zA-Z/\._]+)");
+  var frameRegex = new RegExp("pc ([0-9a-z]+)  ([0-9a-zA-Z/\._-]+)");
   var symbolizedStack = new StringBuffer();
   for (var frameMatch in frameRegex.allMatches(rawStack)) {
     var framePC = frameMatch[1];