For release builds of the JDK, when `javac` is used with `--release N`, the module descriptors for system modules will always contain `N` as their module version, regardless of the current JDK release and update release versions.

For pre-release builds of JDK, the version will contain the pre-release identifiers in addition to `N`.

Previously, the module version encoded in the module descriptors was either missing, for JDK release N, and `--release M`, where M < N, or the full module version, including update versions for JDK release N and `--release N`.