Bug 1508255 - Allow clang-format to reflow comments in js/src r=jandem,arai

Previous patches on this bug fix sources of bad comment reflow. This
patch changes the option in js/src/.clang-format. Doing this puts
SpiderMonkey in-line with Gecko and generates better results from
clang-format.

Depends on D12390

Differential Revision: https://phabricator.services.mozilla.com/D12391

--HG--
extra : moz-landing-system : lando

js/src/.clang-format

@@ -4,8 +4,4 @@ BasedOnStyle: Google
 MacroBlockBegin: "^JS_BEGIN_MACRO$"
 MacroBlockEnd: "^JS_END_MACRO$"
 
-# Ignore all comments because they aren't reflowed properly.
-# We require 80-col comments and 99-col code.
-CommentPragmas: "^"
-
 SortIncludes: false