Fortran: frontend code for F2018 QUIET specifier to STOP and ERROR STOP

Fortran: frontend code for F2018 QUIET specifier to STOP and ERROR STOP

Fortran 2018 allows for a QUIET specifier to the STOP and ERROR STOP
statements.  Whilst the gfortran library code provides support for this
specifier for quite some time, the frontend implementation was missing.

gcc/fortran/ChangeLog:

	PR fortran/84519
	* dump-parse-tree.cc (show_code_node): Dump QUIET specifier when
	present.
	* match.cc (gfc_match_stopcode): Implement parsing of F2018 QUIET
	specifier.  F2018 stopcodes may have non-default integer kind.
	* resolve.cc (gfc_resolve_code): Add checks for QUIET argument.
	* trans-stmt.cc (gfc_trans_stop): Pass QUIET specifier to call of
	library function.

gcc/testsuite/ChangeLog:

	PR fortran/84519
	* gfortran.dg/stop_1.f90: New test.
	* gfortran.dg/stop_2.f: New test.
	* gfortran.dg/stop_3.f90: New test.
	* gfortran.dg/stop_4.f90: New test.