Added a test to cover debugging step over.

tests/standalone/debugger/basic_debugger_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // This test forks a second vm process that runs this dart script as
 // a debug target.
 // Run this test with option --wire to see the json messages sent
 // between the processes.
 // Run this test with option --verbose to see the stdout and stderr output
 // of the debug target process.
 
 import "debug_lib.dart";
 
 bar(x) {
+  var localStr = "foo";
+  int localInt = 1;
+  double localDouble = 1.1;
+  
   print(x);
 }
 
 bam(a) => bar(a);
 
 foo(i) {
   bar("baz");
   print(i);
 }
 
 main() {
   if (RunScript(testScript)) return;
   print("Hello from debuggee");
   foo(42);
   bam("bam");
   print("Hello again");
 }
 
 
 // Expected debugger events and commands.
 var testScript = [
   MatchFrame(0, "main"),  // Top frame in trace is function "main".
   Step(),
   MatchFrame(0, "main"),  // Should still be in "main".
-  SetBreakpoint(15),  // Set breakpoint a line 15, in function bar.
+  SetBreakpoint(19),  // Set breakpoint a line 19, in function bar.
   Resume(),
   MatchFrames(["bar", "foo", "main"]),
   MatchFrame(1, "foo"),
-  SetBreakpoint(18),  // Set breakpoint a line 18, in function bam.
+  MatchLocals({"localStr": '"foo"', "localInt": "1", "localDouble": "1.1", 
+      "x": '"baz"'}),
+  SetBreakpoint(22),  // Set breakpoint a line 22, in function bam.
   Resume(),
   MatchFrames(["bam", "main"]),
   Resume(),
   MatchFrames(["bar", "bam", "main"]),
   Resume(),
 ];