Revert "[RISCV] Fix a vsetvli insertion bug involving loads/stores." and...

Revert "[RISCV] Fix a vsetvli insertion bug involving loads/stores." and "[RISCC] Add missing words to comment. NFC"

This reverts commit f943c58c.
and commit 7eb78107.

This introduced a new bug that appears to be easier to hit.

Differential Revision: https://reviews.llvm.org/D119517

(cherry picked from commit f35ac872)