Raise the intraline diff hard limit from 80 to 100 characters

Summary: Fixes T1246. See PHI637. See T13137. Computers have gotten a bit faster so we can probably bump this up a little and see if it causes problems. This is `O(N^2)` so the this should be less than twice as expensive in the worst case.

Test Plan:
Created a diff affecting characters on a very long line separated by more than 80 but fewer than 100 characters, got a good intraline diff out of it:

{F5605162}

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T1246

Differential Revision: https://secure.phabricator.com/D19442

src/difference/ArcanistDiffUtils.php

@@ -63,7 +63,7 @@ final class ArcanistDiffUtils extends Phobject {
     $ol = strlen($o);
     $nl = strlen($n);
 
-    $max_glyphs = 80;
+    $max_glyphs = 100;
 
     // This has some wiggle room for multi-byte UTF8 characters, and the
     // fact that we're testing the sum of the lengths of both strings. It can