Apply the fix stated in PCRE bug #1423

There is JIT misoptimization found during code refactoring that
affects PCRE 8.34 (the version currently bundled with Qt).

The upstream might not release a specific bugfix release before 8.35,
hence the patch has been manually applied.

Upstream issue: http://bugs.exim.org/show_bug.cgi?id=1423

Change-Id: I8dbbb2981bc037d39b30fcaded6894ee9820b8df
Reviewed-by: Lars Knoll <lars.knoll@digia.com>