In java.go, add implement check for both Dependency and IDE relevant interfaces

1. Add var _ to declare the struct Import implement IDEInfo and
   IDECustomizedModuleName interfaces
2. Modify var _, a typo case for struct Module implement Dependency interface
3. Add nil checking for Dependency interface implementation
4. Add more comment for developer

Bug: 121985695

Test: 1. m aidegen
      2. $ANDROID_HOST_OUT/bin/aidegen framework
      3. check import static android.Manifest.permission.BIND_VOICE_INTERACTION;
	 denpendency should be resolved in frameworks/base/services/core/java/com/android/server/am/ActivityManagerService.java

Change-Id: Ia2d2d65b83a52d35ccb3927a36bcf686d5223e20