Bug: Invalid glyph displayed for character

Created by: balagge

Issue Summary

Character [U+2246 ≆ APPROXIMATELY BUT NOT ACTUALLY EQUAL TO] is displayed incorrectly by default.

Steps to Reproduce

E.g. in the online demo version at https://www.mathjax.org/#demo the following MathML renders all 3 occurrences (verbatim, hexadecimal / named entity) of the character incorrectly.

<math>
  <mi>a</mi>
  <mo>≆</mo>
  <mi>b</mi>
  <mo>&#x2246;</mo>
  <mi>c</mi>
  <mo>&simne;</mo>
  <mi>d</mi>
</math>

Expected rendering

The expected / correct glyph should be similar to the example below:

http://www.fileformat.info/info/unicode/char/2246/approximately_but_not_actually_equal_to.png

Actual rendering

What is actually displayed is the glyph of another character, [U+2247 ≇ NEITHER APPROXIMATELY NOR ACTUALLY EQUAL TO]:

http://www.fileformat.info/info/unicode/char/2247/neither_approximately_nor_actually_equal_to.png

Technical details

MathJax Version: current demo version
Client OS: Ubuntu 14.04
Browser: Firefox / Chromium
Renderer: HTML-CSS, Common HTML, SVG

Note: the preview HTML and the MathML renderer (if using Firefox, which has built-in MathML rendering) displays a correct glyph. So this is probably a font error.