Bug 1105052 - Update in-tree jsmin to commit a878bf0. rs=gps

This is a straight copy from

a878bf0ba0

paired with a tiny change to use the new quote_chars option.

python/mozbuild/mozpack/files.py

@@ -609,7 +609,7 @@ class MinifiedJavaScript(BaseFile):
 
     def open(self):
         output = BytesIO()
-        minify = JavascriptMinify(self._file.open(), output)
+        minify = JavascriptMinify(self._file.open(), output, quote_chars="'\"`")
         minify.minify()
         output.seek(0)