Merge #135692: pkgsCross.avr.buildPackages.gcc: work around

... for log limit on hydra

pkgs/development/compilers/gcc/10/default.nix

···
     else "")
       + lib.optionalString targetPlatform.isAvr ''
             makeFlagsArray+=(
+               '-s' # workaround for hitting hydra log limit
                'LIMITS_H_TEST=false'
             )
           '';

pkgs/development/compilers/gcc/11/default.nix

···
     else "")
       + lib.optionalString targetPlatform.isAvr ''
             makeFlagsArray+=(
+               '-s' # workaround for hitting hydra log limit
                'LIMITS_H_TEST=false'
             )
           '';