PR fortran/95373 - ICE in build_reference_type, at tree.c:7942

PR fortran/95373 - ICE in build_reference_type, at tree.c:7942

The use of KIND, LEN, RE, and IM inquiry references for applicable intrinsic
types is valid only for suffienctly new Fortran standards.  Add appropriate
check.

2020-05-28  Harald Anlauf  <anlauf@gmx.de>

gcc/fortran/
	PR fortran/95373
	* primary.c (is_inquiry_ref): Check validity of inquiry
	references against selected Fortran standard.

gcc/testsuite/
	PR fortran/95373
	* gfortran.dg/pr95373_1.f90: New test.
	* gfortran.dg/pr95373_2.f90: New test.