Improve fast forward search in JIT.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@1419 2f5784b3-3f2a-0410-8824-cb99058d5e15
Improve character range checks in JIT.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@1420 2f5784b3-3f2a-0410-8824-cb99058d5e15