[Fortran/gfortran] Disable failing test (#249)

This test should fail to compile with an "invalid character in name" error - or
the equivalent in flang. However, it used to fail because the LINEAR clause was
not implemented in the OpenMP DO construct. The clause is now supported.
However, flang does not issue the expected compile-time error which causes the
test to fail.

Author: tarunprabhu

Fortran/gfortran/regression/gomp/DisabledFiles.cmake

@@ -407,6 +407,7 @@ file(GLOB FAILING_FILES CONFIGURE_DEPENDS
   #
   canonical-loop-2.f90
   crayptr2.f90
+  linear-8.f90
   polymorphic-mapping-4.f90
   polymorphic-mapping-5.f90
   pr33439.f90