[mlir] [integration_test] Add XFAIL for "flang-aarch64-ubuntu" reduction failures

[mehdi_amini]

This seems like something which should be in a lit.local.cfg instead of individual tests.

Also a "whitelist" of where it is expected to work seems more suitable than a blacklist.

mlir/integration_test/Dialect/Vector/CPU/test-reductions-f32.mlir

 // RUN: mlir-opt %s -convert-scf-to-std -convert-vector-to-llvm -convert-std-to-llvm | \
 // RUN: mlir-cpu-runner -e entry -entry-point-result=void  \
 // RUN:   -shared-libs=%mlir_integration_test_dir/libmlir_c_runner_utils%shlibext | \
 // RUN: FileCheck %s
+//
+// TODO(ajcbik): fix for flang-aarch64-ubuntu
+// XFAIL: aarch64
 
 func @entry() {
   // Construct test vector.
   %f1 = constant 1.5: f32
   %f2 = constant 2.0: f32
   %f3 = constant 3.0: f32
   %f4 = constant 4.0: f32
   %f5 = constant 5.0: f32

mlir/integration_test/Dialect/Vector/CPU/test-reductions-f64.mlir

 // RUN: mlir-opt %s -convert-scf-to-std -convert-vector-to-llvm -convert-std-to-llvm | \
 // RUN: mlir-cpu-runner -e entry -entry-point-result=void  \
 // RUN:   -shared-libs=%mlir_integration_test_dir/libmlir_c_runner_utils%shlibext | \
 // RUN: FileCheck %s
+//
+// TODO(ajcbik): fix for flang-aarch64-ubuntu
+// XFAIL: aarch64
 
 func @entry() {
   // Construct test vector.
   %f1 = constant 1.5: f64
   %f2 = constant 2.0: f64
   %f3 = constant 3.0: f64
   %f4 = constant 4.0: f64
   %f5 = constant 5.0: f64

mlir/integration_test/Dialect/Vector/CPU/test-reductions-i64.mlir

 // RUN: mlir-opt %s -convert-scf-to-std -convert-vector-to-llvm -convert-std-to-llvm | \
 // RUN: mlir-cpu-runner -e entry -entry-point-result=void  \
 // RUN:   -shared-libs=%mlir_integration_test_dir/libmlir_c_runner_utils%shlibext | \
 // RUN: FileCheck %s
+//
+// TODO(ajcbik): fix for flang-aarch64-ubuntu
+// XFAIL: aarch64
 
 func @entry() {
   // Construct test vector.
   %i1 = constant 1: i64
   %i2 = constant 2: i64
   %i3 = constant 3: i64
   %i4 = constant 4: i64
   %i5 = constant 5: i64