Revert "Use new Svt_INVLIST for inversion lists."

This reverts commit e0ce103ae532f9576f54a5938a24d1ee98dfb928.
This commit is failing compilations with address sanitizer, and we don't
know why.  This reverts it while we work that out.
PATCH: [perl #114178] di/ds/ig exempt from warnings in void context
op.c: White-space only

Outdent to correspond with removed block