Deprecate Math object in corelib in favor of dart:math library.

pkg/intl/lib/date_format_helpers.dart

Index: pkg/intl/lib/date_format_helpers.dart
diff --git a/pkg/intl/lib/date_format_helpers.dart b/pkg/intl/lib/date_format_helpers.dart
index 3deda226ebda9b51dae75e5f225e0933ff0cb526..6ac16b9b4bc72f520ef5406d20dad0d477a214fd 100644
--- a/pkg/intl/lib/date_format_helpers.dart
+++ b/pkg/intl/lib/date_format_helpers.dart
@@ -87,7 +87,7 @@ class _Stream {
     if (contents is String) {
       result = contents.substring(
           index,
-          Math.min(index + howMany, contents.length));
+          min(index + howMany, contents.length));
     } else {
       // Assume List
       result = contents.getRange(index, howMany);
@@ -130,6 +130,6 @@ class _Stream {
     var string = digitMatcher.stringMatch(rest());
     if (string == null || string.isEmpty()) return null;
     read(string.length);
-    return Math.parseInt(string);
+    return parseInt(string);
   }
-}
+}