[Fortran/gfortran] Disable little endian test on big endian target (#248)

The disabled test is designed for little endian environment.

Author: kkwli

Fortran/gfortran/regression/override.yaml

@@ -183,3 +183,8 @@
 # this is not worth marking as "permanently unsupported".
 "diagnostic-format-sarif-1.F90":
   xfail: true
+
+# This test case is designed for little endian target. Disable the test case
+# on big endian target.
+"unsigned_21.f90":
+  disabled_on: ["powerpc-*-aix"]

Fortran/gfortran/regression/tests.cmake

@@ -6561,7 +6561,7 @@ run;unsigned_18.f90;;-funsigned;;
 run;unsigned_19.f90;;-funsigned;;
 run;unsigned_2.f90;;-funsigned;;
 run;unsigned_20.f90;;-funsigned;;
-run;unsigned_21.f90;;-funsigned;;
+run;unsigned_21.f90;;-funsigned;;powerpc-.+-aix
 run;unsigned_21_be.f90;;-funsigned;;
 run;unsigned_22.f90;;-funsigned -pedantic;;
 run;unsigned_23.f90;;-funsigned;;