Tests with breakpoint set being skipped when using --pause-after-load

[TimIrwin26]

Transferred over from dart-lang/test#409

When attempting to debug unit tests running on either content-shell or Dartium, any group where I set a breakpoint in one of the tests using browser developer tools ends up skipped.

In the second test run, I set a breakpoint in one of the tests during the "pause-after-load" using Chrome developer tools. The tests run fine if "--pause-after-load" is used with no browser breakpoints.

• OSX 10.11.3
• Dart 1.15.0
• test 1.12.12
• Current version of Chrome (or Dartium shipped in Homebrew package w/ Dart 1.15.0)
• Also reproduces on Ubuntu with a similar setup.

pro:~/sandbox/unit_test$ pub run test -p content-shell test/some_test.dart 
00:04 +0: A should fail                                                                            
abc
00:04 +0 -1: A should fail                                                                         
  Expected: <false>
    Actual: <true>

  package:test         expect
  some_test.dart 11:7  main.<fn>.<fn>

00:04 +0 -1: B should pass                                                                         
abc
00:04 +1 -1: C all called                                                                          
[should fail, should pass]
00:04 +2 -1: Some tests failed.          

pro:~/sandbox/unit_test$ pub run test -p content-shell test/some_test.dart --pause-after-load
00:04 +0: loading test/some_test.dart                                                              

Observatory URL: http://127.0.0.1:51847
Remote debugger URL: http://localhost:51837/devtools/inspector.html?ws=localhost:51837/devtools/page/7341D459-82CC-47A9-9C3C-6A77CA1CF37D
The test runner is paused. Open the remote debugger or the Observatory and set breakpoints. Once
you're finished, return to this terminal and press Enter.

00:04 +0: All tests skipped.      

pubspec.yaml.txt
some_test.dart.txt

[terrylucas]

Please test with 1.17.1 Stable or 1.18 Dev channel. There was a recent fix where BPs were not handled (cross frame).