[Fortran/goacc] Disable routine-3 (llvm#271)

The test routine-3 fails after:
llvm/llvm-project#149614

This is because the OpenACC spec requires for all
do loop induction variables to be privatized, but
the private recipe does not yet have a materialization
implementation. Thus disable it in the same way other
tests in same category fail.

Author: razvanlupusoru

Fortran/gfortran/regression/goacc/DisabledFiles.cmake

@@ -91,6 +91,7 @@ file(GLOB SKIPPED_FILES CONFIGURE_DEPENDS
   private-explicit-parallel-1.f95
   private-explicit-serial-1.f95
   private-predetermined-serial-1.f95
+  routine-3.f90
   serial-tree.f95
 
   # error: unsupported OpenACC operation: acc.reduction