ipa-sra: Check also ECF_LOOPING_CONST_OR_PURE when evaluating calls

ipa-sra: Check also ECF_LOOPING_CONST_OR_PURE when evaluating calls

in PR 103267 Honza found out that IPA-SRA does not look at
ECF_LOOPING_CONST_OR_PURE when evaluating if a call can have side
effects.  Fixed with this patch.  The testcase infinitely loops in a
const function, so it would not make a good addition to the testsuite.

gcc/ChangeLog:

2021-11-29  Martin Jambor  <mjambor@suse.cz>

	PR ipa/103267
	* ipa-sra.c (scan_function): Also check ECF_LOOPING_CONST_OR_PURE flag.

(cherry picked from commit e5440bc08e07fd491dcccd47e1b86a5985ee117c)