Don't move the closing tag of POSIX capture group out of the enclosing iteration.

Don't move the closing tag of POSIX capture group out of the enclosing iteration.

RE2C used to perform the following optimization: when a POSIX capture is
under iteration, we only need to get tag values of the last iteration
(according to the POSIX standard). Therefore we can move the closing tag
out of loop.

This commit removes this optimization (as part of the effort to switch
from Kuklewicz POSIX disambiguation algorthm to Okui algorithm).

In other words, for RE (x)* re2c used to generate this "optimized" IRE:
    1 (3 x)* 4 2
and now it generates the "canonical" IRE:
    1 (3 x 4)* 2

Updated tests for '--posix-captures' that have been affected by the change.