match: Keep conditional in simplification to constant [PR118140].

In PR118140 we simplify

  _ifc__33 = .COND_IOR (_41, d_lsm.7_11, _46, d_lsm.7_11);

to 1:

Match-and-simplified .COND_IOR (_41, d_lsm.7_11, _46, d_lsm.7_11) to 1

when _46 == 1.  This happens by removing the conditional and applying
a | 1 = 1.  Normally we re-introduce the conditional and its else value
if needed but that does not happen here as we're not dealing with a
vector type.  For correctness's sake, we must not remove the conditional
even for non-vector types.

This patch re-introduces a COND_EXPR in such cases.  For PR118140 this
result in a non-vectorized loop.

	PR middle-end/118140

gcc/ChangeLog:

	* gimple-match-exports.cc (maybe_resimplify_conditional_op): Add
	COND_EXPR when we simplified to a scalar gimple value but still
	have an else value.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/pr118140.c: New test.
	* gcc.target/riscv/rvv/autovec/pr118140.c: New test.