aot-smoke-test-support doesn't set Java version

[mhalbritter]

aot-smoke-test-support should set Java version to 17 to make it possible to test with newer Graal releases. Right now, running against Graal 23 gives this error:

Could not determine the dependencies of task ':boot:actuator-webmvc:appTest'.
> Could not resolve all dependencies for configuration ':boot:actuator-webmvc:appTestRuntimeClasspath'.
   > Could not resolve project :aot-smoke-test-support.
     Required by:
         project :boot:actuator-webmvc
      > Dependency resolution is looking for a library compatible with JVM runtime version 17, but 'project :aot-smoke-test-support' is only compatible with JVM runtime version 23 or newer.

[mhalbritter]

Done in 19979a0.