'gfortran.dg/assumed_rank_22_aux.c' messages printed vs. DejaGnu

'gfortran.dg/assumed_rank_22_aux.c' messages printed vs. DejaGnu

Print lower-case 'error: [...]' instead of upper-case 'ERROR: [...]', to not
confuse the DejaGnu log processing harness into thinking these are DejaGnu
harness ERRORs:

    Running /scratch/tschwing/build2-trusty-cs/gcc/build/submit-big/source-gcc/gcc/testsuite/gfortran.dg/dg.exp ...
    +ERROR: c_assumed num=100: x->dim[2].extent = -1 != 0
    +ERROR: c_assumed num=100: x->dim[2].extent = -1 != 0
    +ERROR: c_assumed num=100: x->dim[2].extent = -1 != 0
    +ERROR: c_assumed num=100: x->dim[2].extent = -1 != 0
    +ERROR: c_assumed num=100: x->dim[2].extent = -1 != 0
    +ERROR: c_assumed num=100: x->dim[2].extent = -1 != 0
    [...]

Fix-up for recent commit 00f6de9c69119594f7dad3bd525937c94c8200d0
"Fortran: Fix assumed-size to assumed-rank passing [PR94070]".

	gcc/testsuite/
	* gfortran.dg/assumed_rank_22_aux.c: Adjust messages printed.