lim/cselim: Use lhs_could_trap_p directly instead of inline

Instead of calling tree_could_trap_p and then testing decl/string,
we can just use lhs_could_trap_p.
This will be used by the next patch to fix `this->a` accesses.

Bootstrapped and tested on x86_64-linux-gnu.

gcc/ChangeLog:

	* tree-ssa-loop-im.cc (can_sm_ref_p): Use lhs_could_trap_p.
	* tree-ssa-phiopt.cc (cond_store_replacement): Likewise.

Signed-off-by: Andrea Pinski <andrew.pinski@oss.qualcomm.com>