OpenJDK 11: Merging sun.nio.ch.* trivial changes

This is a part of merging upstream changes from OpenJDK 11.28. It
updates classes with trivial changes (most of them are javadoc
changes).

Bug: 198640665
Test: m
Change-Id: I46ccbd21bcf43a49902d2d65adc254db0a665311
9 files changed