8207032: Compilation succeeds without checking readability when --add-exports used
Summary: Ensuring --add-exports are only propagated when the target module reads the exporting module.
Reviewed-by: vromero, jjg
8189747: JDK9 javax.lang.model.util.Elements#getTypeElement regressed 1000x in performance.
Summary: Caching the results of Elements.getTypeElement/getPackageElement
Reviewed-by: darcy