kfdtest: Quote all CXX flags

Otherwise it doesn't play nicely with -O2
Change-Id: I2e5b60c73ee1ec668b186088a4e2e3a03af65033

tests/kfdtest/CMakeLists.txt

@@ -167,7 +167,7 @@ endif ()
 
 ## Address Sanitize Flag
 if ( ${ADDRESS_SANITIZER} )
-    set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}" -fsanitize=address )
+    set ( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fsanitize=address" )
     set ( CMAKE_EXE_LINKER_FLAGS -fsanitize=address )
 endif ()