if-conv: Restore MASK_CALL conversion [PR108888]

if-conv: Restore MASK_CALL conversion [PR108888]

The original patch to fix this PR broke the if-conversion of calls into
IFN_MASK_CALL.  This patch restores that original behaviour and makes sure the
tests added earlier specifically test inbranch SIMD clones.

gcc/ChangeLog:

	PR tree-optimization/108888
	* tree-if-conv.cc (predicate_statements): Fix gimple call check.

gcc/testsuite/ChangeLog:

	* gcc.dg/vect/vect-simd-clone-16.c: Make simd clone inbranch only.
	* gcc.dg/vect/vect-simd-clone-17.c: Likewise.
	* gcc.dg/vect/vect-simd-clone-18.c: Likewise.