c++: improved return expression location

c++: improved return expression location

Stripping the location wrapper from retval meant we didn't have the
necessary location information for any conversion diagnostics.  We only need
the stripping for the named return value optimization, let's use the
unstripped expression for everything else.

gcc/cp/ChangeLog:

	* typeck.c (check_return_expr): Only strip location wrapper during
	NRV handling.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/pr65327.C: Adjust location.
	* g++.dg/cpp23/constexpr-nonlit4.C: Likewise.
	* g++.dg/cpp23/constexpr-nonlit5.C: Likewise.
	* g++.dg/cpp2a/constexpr-init1.C: Likewise.