[AOT] Using AOT flag should give warning when AOT is not included in build

Currently if AOT is not included in a build AOT flags specified on command line are silently ignored:

$ java -XX:+UnlockExperimentalVMOptions -XX:+UseAOT -version
java version "16-internal" 2021-03-16
Java(TM) SE Runtime Environment (fastdebug build 16-internal+0-2020-11-04-2338514)
Java HotSpot(TM) 64-Bit Server VM (fastdebug build 16-internal+0-2020-11-04-2338514, mixed mode, sharing)

We should give warning that AOT is not supported in such builds.