OpenJDK 11: Merge java.nio.file.FileStore.

Adds a new API, FileStore.getBlockSize().

The implementation in this class throws UnsupportedOperationException
and there are no other implementations in subclasses. I propose that
we add the new API and when we merge sun.nio.* add an Android
implementation and tests.

Bug: 203426354
Test: TreeHugger
Change-Id: I29691c4b73d946943270e41d69ea25feef7379b3
2 files changed