c++: alias template of non-template class [PR112633]

c++: alias template of non-template class [PR112633]

The entering_scope adjustment in tsubst_aggr_type assumes if an alias is
dependent, then so is the aliased type (and therefore it has template info)
but that's not true for the dependent alias template specialization ty1<T>
below which aliases the non-template class A.  In this case no adjustment
is needed anyway, so we can just punt.

	PR c++/112633

gcc/cp/ChangeLog:

	* pt.cc (tsubst_aggr_type): Handle empty TYPE_TEMPLATE_INFO
	in the entering_scope adjustment.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/alias-decl-75.C: New test.