Allow breakpoints on one-liner functions

tests/standalone/debugger/basic_debugger_test.dart

Index: tests/standalone/debugger/basic_debugger_test.dart
===================================================================
--- tests/standalone/debugger/basic_debugger_test.dart	(revision 22797)
+++ tests/standalone/debugger/basic_debugger_test.dart	(working copy)
@@ -15,6 +15,8 @@
   print(x);
 }
 
+bam(a) => bar(a);
+
 foo(i) {
   bar("baz");
   print(i);
@@ -24,6 +26,7 @@
   if (RunScript(testScript)) return;
   print("Hello from debuggee");
   foo(42);
+  bam("bam");
   print("Hello again");
 }
 
@@ -37,5 +40,10 @@
   Resume(),
   MatchFrames(["bar", "foo", "main"]),
   MatchFrame(1, "foo"),
+  SetBreakpoint(18),  // Set breakpoint a line 18, in function bam.
   Resume(),
+  MatchFrames(["bam", "main"]),
+  Resume(),
+  MatchFrames(["bar", "bam", "main"]),
+  Resume(),
 ];