[3.12] gh-67877: Fix memory leaks in terminated RE matching (GH-126840) (GH-126961)

If SRE(match) function terminates abruptly, either because of a signal
or because memory allocation fails, allocated SRE_REPEAT blocks might
be never released.

(cherry picked from commit 7538e7f5696408fa0aa02fce8a413a7dfac76a04)