VERB nodes in the regex engine should NOT be marked as JUMPABLE.

VERB nodes in the regex engine should NOT be marked as JUMPABLE.

JUMPABLE nodes can be ignored during certain phases of regex execution,
including ones where backtracking is affected. This change disables this
behviour so that the VERBS can perform their desired results.

Committer has taken the liberty of modifying the patch so that all
VERBS are jumped, thus making the JUMPABLE expression a little simpler.
I have left Bram's change to JUMPABLE intact, but inside of a comment
for now.

See discussion in thread for [perl #71942] *COMMIT bypasses optimisation
for futher details.

http://rt.perl.org/rt3/Ticket/Display.html?id=71942

There appears to be room for futher optimisation here
by moving the JUMPABLE logic to regex-compile time. Currently
it is arguable that the "optimisation" this patch seeks to avoid
is actually not an optimisation at all, as it happens OVER AND OVER
during execution of a match, thus the extra effort might actually
outweight the benefit, especially on large strings.