[compiler-rt] [test] Build sanitizer/xray tests only if COMPILER_RT_BUILD_* is on

[mgorny]

Summary

Cover the sanitizer tests with COMPILER_RT_BUILD_SANITIZERS
conditional, and add COMPILER_RT_BUILD_XRAY conditional to the xray
tests. This makes it possible to do a pure-builtins build with tests
enabled.

test/CMakeLists.txt

 endif()
 
 # Run sanitizer tests only if we're sure that clang would produce
 # working binaries.
 if(COMPILER_RT_CAN_EXECUTE_TESTS)
   if(COMPILER_RT_BUILD_BUILTINS)
     add_subdirectory(builtins)
   endif()
+  if(COMPILER_RT_BUILD_SANITIZERS)
     if(COMPILER_RT_HAS_ASAN)
       add_subdirectory(asan)
     endif()
     if(COMPILER_RT_HAS_DFSAN)
       add_subdirectory(dfsan)
     endif()
     if (COMPILER_RT_HAS_INTERCEPTION)
       add_subdirectory(interception)
     endif()
     if(COMPILER_RT_HAS_LSAN)
       add_subdirectory(lsan)
     endif()
     if(COMPILER_RT_HAS_MSAN)
       add_subdirectory(msan)
     endif()
     if(COMPILER_RT_HAS_PROFILE)
       add_subdirectory(profile)
     endif()
     if(COMPILER_RT_HAS_SANITIZER_COMMON)
       add_subdirectory(sanitizer_common)
     endif()
     if(COMPILER_RT_HAS_TSAN)
       add_subdirectory(tsan)
     endif()
     if(COMPILER_RT_HAS_UBSAN)
       add_subdirectory(ubsan)
     endif()
     # CFI tests require diagnostic mode, which is implemented in UBSan.
     if(COMPILER_RT_HAS_UBSAN)
       add_subdirectory(cfi)
     endif()
     if(COMPILER_RT_HAS_SAFESTACK)
       add_subdirectory(safestack)
     endif()
     if(COMPILER_RT_HAS_ESAN)
       add_subdirectory(esan)
     endif()
     if(COMPILER_RT_HAS_SCUDO)
       add_subdirectory(scudo)
     endif()
-  if(COMPILER_RT_HAS_XRAY)
+  endif()
+  if(COMPILER_RT_BUILD_XRAY AND COMPILER_RT_HAS_XRAY)
     add_subdirectory(xray)
   endif()
 endif()
 
 if(COMPILER_RT_STANDALONE_BUILD)
   # Now that we've traversed all the directories and know all the lit testsuites,
   # introduce a rule to run to run all of them.
   get_property(LLVM_LIT_TESTSUITES GLOBAL PROPERTY LLVM_LIT_TESTSUITES)