[CMake] Print out the list of sanitizers that the sanitizer_common tests will run against.

[delcypher]

Summary

This is a change requested by Vitaly Buka as prerequisite to landing
https://reviews.llvm.org/D55740.

test/sanitizer_common/CMakeLists.txt

if(CMAKE_SYSTEM_NAME MATCHES "NetBSD" OR (CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT ANDROID))
   list(APPEND SUPPORTED_TOOLS tsan)
   list(APPEND SUPPORTED_TOOLS msan)
   list(APPEND SUPPORTED_TOOLS ubsan)
 endif()
 if(CMAKE_SYSTEM_NAME MATCHES "Linux" AND NOT ANDROID)
   list(APPEND SUPPORTED_TOOLS lsan)
 endif()
 
+# FIXME(dliew): Remove this.
+# Temporary helper for https://reviews.llvm.org/D55740
+message(
+  STATUS
+  "sanitizer_common tests on \"${CMAKE_SYSTEM_NAME}\" will run against "
+  "\"${SUPPORTED_TOOLS}\"")
+
 # Create a separate config for each tool we support.
 foreach(tool ${SUPPORTED_TOOLS})
   string(TOUPPER ${tool} tool_toupper)
   if(${tool_toupper}_SUPPORTED_ARCH AND NOT COMPILER_RT_STANDALONE_BUILD)
     list(APPEND SANITIZER_COMMON_TEST_DEPS ${tool})
   endif()
   set(TEST_ARCH ${${tool_toupper}_SUPPORTED_ARCH})
   if(APPLE)