Fix up gfortran.dg/gomp/allocate-*.f90

The r17-1009 change (in particular gfc_match_omp_variable_list hunk
of it) fixed spelling of one diagnostic message, but has not adjusted
corresponding testsuite, so these tests now fail.

Fixed thusly.

2026-06-02  Jakub Jelinek  <jakub@redhat.com>

	* gfortran.dg/gomp/allocate-6.f90: Adjust dg-error wording after
	recent spelling fixes.
	* gfortran.dg/gomp/allocate-7.f90: Likewise.
	* gfortran.dg/gomp/allocate-14.f90: Likewise.
	* gcc.target/sparc/struct-ret-check-1.c: Fix comment spelling,
	specificed -> specified.