Add missing / improve existing change markers in sun.net.

Files in this package are currently based on an OpenJDK 7u40 upstream.
This CL ensures proper documentation for Android changes in this
package. The work to update this package to a later upstream is left
to a follow-up CL.

Bug: 38027507
Test: Treehugger build succeeds.
Change-Id: I7204e8ab57928a98e107f44ad62d4973355f5c3a
6 files changed