Keep only a single active stack trace, enables traces for thrown non-exceptions

pkg/dev_compiler/test/browser/language_tests.js

Index: pkg/dev_compiler/test/browser/language_tests.js
diff --git a/pkg/dev_compiler/test/browser/language_tests.js b/pkg/dev_compiler/test/browser/language_tests.js
index af33d476e21ac129f77e77c5dc921ff42767807a..ea909a4b2c2c167d702320a4fd489f28ae1724cd 100644
--- a/pkg/dev_compiler/test/browser/language_tests.js
+++ b/pkg/dev_compiler/test/browser/language_tests.js
@@ -275,8 +275,6 @@ define(['dart_sdk', 'async_helper', 'expect', 'unittest', 'is', 'require'],
       'setter_no_getter_test_01_multi': skip_fail,
       'stack_overflow_stacktrace_test': skip_fail,
       'stack_overflow_test': skip_fail,
-      'stack_trace_test': skip_fail,
-      'stacktrace_rethrow_nonerror_test': skip_fail, // mismatch from Karma's file hash
       'stacktrace_rethrow_error_test_none_multi': skip_fail,
       'stacktrace_rethrow_error_test_withtraceparameter_multi': skip_fail,
       'stacktrace_test': skip_fail,
@@ -377,7 +375,6 @@ define(['dart_sdk', 'async_helper', 'expect', 'unittest', 'is', 'require'],
       'regress_r21715_test': fail,
       'throw_half_surrogate_pair_test_02_multi': fail,
       'splay_tree_from_iterable_test': firefox_fail,
-      'stacktrace_current_test': chrome_fail,
       'string_case_test_01_multi': firefox_fail,
       'string_fromcharcodes_test': skip_timeout,
       'string_operations_with_null_test': fail,