[UBSan] Also use blacklist for 'Address; Undefined' setting

[fhahn]

Summary

It looks like currently the UBSan blacklist is only applied when "Undefined" is selected.
This patch updates the cmake file to apply it whenever Undefined is selected
(e.g. 'Address; Undefined' ). This allows us to use the workaround added in
rL335525 when using AddressSan and UBSan together.

cmake/modules/HandleLLVMOptions.cmake

if (LLVM_ON_UNIX)
     elseif (LLVM_USE_SANITIZER STREQUAL "Thread")
       append_common_sanitizer_flags()
       append("-fsanitize=thread" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
     elseif (LLVM_USE_SANITIZER STREQUAL "Address;Undefined" OR
             LLVM_USE_SANITIZER STREQUAL "Undefined;Address")
       append_common_sanitizer_flags()
       append("-fsanitize=address,undefined -fno-sanitize=vptr,function -fno-sanitize-recover=all"
               CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+      set(BLACKLIST_FILE "${CMAKE_SOURCE_DIR}/utils/sanitizers/ubsan_blacklist.txt")
+      if (EXISTS "${BLACKLIST_FILE}")
+        append("-fsanitize-blacklist=${BLACKLIST_FILE}"
+                CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
+      endif()
     elseif (LLVM_USE_SANITIZER STREQUAL "Leaks")
       append_common_sanitizer_flags()
       append("-fsanitize=leak" CMAKE_C_FLAGS CMAKE_CXX_FLAGS)
     else()
       message(FATAL_ERROR "Unsupported value of LLVM_USE_SANITIZER: ${LLVM_USE_SANITIZER}")
     endif()
   elseif(MSVC)
     if (LLVM_USE_SANITIZER STREQUAL "Address")