[JVMCI] -XX:+EnableJVMCIProduct breaks -XX:-EnableJVMCI

The -XX:+EnableJVMCIProduct option (added by JDK-8232118) currently sets the default values of EnableJVMCI and UseJVMCICompiler. If these options are also explicitly on the command line, these explicit values should take precedence. For example:

java -XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCIProduct -XX:-UnlockExperimentalVMOptions -XX:-EnableJVMCI

should result in JVMCI being completely disabled. While this command line may look strange, it can occur when `-XX:+UnlockExperimentalVMOptions -XX:+EnableJVMCIProduct -XX:-UnlockExperimentalVMOptions` is on the command line due to use of the jlink --add-options flag. This is exactly what's done when creating a GraalVM binary.

Currently, the above command line results in a false error:

Improperly specified VM option UseJVMCICompiler: EnableJVMCI cannot be disabled