Tolerate null from finding browser locale, re-enable tests

pkg/pkg.status

Index: pkg/pkg.status
===================================================================
--- pkg/pkg.status	(revision 14088)
+++ pkg/pkg.status	(working copy)
@@ -21,22 +21,11 @@
 intl/test/date_time_format_file_odd_test: Skip
 intl/test/find_default_locale_standalone_test: Skip
 
-[ $runtime == ie9 && $compiler == dart2js ]
-intl/test/find_default_locale_browser_test: Skip # Issue 6176
-
 # Skip browser-specific Intl tests on VM
 [ $runtime == vm ]
 intl/test/find_default_locale_browser_test: Skip
 intl/test/date_time_format_http_request_test: Skip
 
-# Skip http request tests on Dartium while resolving an odd
-# error there that causes the tests to timeout.
-[ $runtime == dartium || $runtime == drt ]
-intl/test/date_time_format_http_request_test: Skip
-
-[ $compiler == dart2js && $runtime == ff ]
-intl/test/date_time_format_http_request_test: Skip # Issue 5649
-
 # Skip intl_message tests that use mirrors on dart2js until it's been
 # implemented there.
 [ $compiler == dart2js ]