Fortran: improve checking of assumed-size array spec [PR102180]

gcc/fortran/ChangeLog:

	PR fortran/102180
	* array.cc (match_array_element_spec): Add check for bad
	assumed-implied-spec.
	(gfc_match_array_spec): Reorder logic so that the first bad array
	element spec may trigger an error.

gcc/testsuite/ChangeLog:

	PR fortran/102180
	* gfortran.dg/pr102180.f90: New test.