c++: Fix qualified array-type construction [PR 98538]

c++: Fix qualified array-type construction [PR 98538]

This was an assert that was too picky.  The reason I had to alter
array construction was that on stream in, we cannot dynamically determine
a type's dependentness.  Thus on stream out of the 'problematic' types,
we save the dependentness for reconstruction.  Fortunately the paths into
cp_build_qualified_type_real from streamin with arrays do have the array's
dependentess set as needed.

	PR c++/98538
	gcc/cp/
	* tree.c (cp_build_qualified_type_real): Propagate an array's
	dependentness to the copy, if known.
	gcc/testsuite/
	* g++.dg/template/pr98538.C: New.