Fibonacci regex, fastest: Take advantage of a new RegexMathEngine optimization; length-=15
[empty commit to get the merge to work]
Fibonacci regex, fastest: Rename this version to reflect its engine-specific optimizations
Merge branch 'RegexMathEngine-optimizations'
Fibonacci regex, fastest: Fix false negative at 144; length-=1

This bug was introduced in commit 6d5fbede86c4ce022d020d18a5a526a18fe589cc