preprocessor: Make quoting : [PR 95253]

I missed some testsuite fall out with my patch to fix mkdeps file
mangling.

	PR preprocessor/95253
	gcc/testsuite/
	* g++.dg/modules/dep-1_a.C: Adjust expected output.
	* g++.dg/modules/dep-1_b.C: Likewise.
	* g++.dg/modules/dep-2.C: Likewise.