Ada: adjust pattern matching to new stack probes on x86/Linux

This fixes the couple of ACATS regressions introduced by the change:

                === acats tests ===
FAIL:  c52103x
FAIL:  c52104x

gcc/ada/
	PR target/124336
	* init.c (__gnat_adjust_context_for_raise) [x86/Linux]: Adjust
	pattern matching to new stack probes.