[test-suite] Disable AArch64 tests for OSX arm64 to fix green dragon.

[asbirlea]

Summary

On OSX-arm64, the halide runtime is not properly linked in with
the simd_ops tests leading to missing symbols.
Temporary disable tests for OSX-arm64 to make green dragon green again.

[mehdi_amini]

Whatever can make the bot green again.

Thanks!

Bitcode/CMakeLists.txt

 # We need at least clang 3.9 to process the bitcode here.
 if(CMAKE_C_COMPILER_ID STREQUAL "Clang" AND
     CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND
     NOT CMAKE_C_COMPILER_VERSION VERSION_LESS "3.9" AND
     NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS "3.9")
   set(ENABLE_BITCODE_DEFAULT "True")
 endif()
 
 set(TEST_SUITE_ENABLE_BITCODE_TESTS ${ENABLE_BITCODE_DEFAULT} CACHE BOOL "Enable bitcode tests")
 if(TEST_SUITE_ENABLE_BITCODE_TESTS)
   if(NOT TEST_SUITE_BENCHMARKING_ONLY)
     llvm_add_subdirectories(Regression)
     if(ARCH STREQUAL "x86" OR ARCH STREQUAL "AArch64" OR ARCH STREQUAL "ARM")
+      #FIXME: Disable AArch64 tests until clarifying why the halide runtime is not linked on green dragon
+      if (NOT CMAKE_OSX_ARCHITECTURES STREQUAL "arm64")
         llvm_add_subdirectories(simd_ops)
       endif()
     endif()
   endif()
+endif()