Verify java.util.{Collections,List} vs. OpenJDK 8u121-b13.

Tweak existing change markers; no behavior changes.

For the missing Iterator.forEachRemaining() overrides, add
a reference to a bug that has more context and contains a
unit test that demonstrates the oversight.
One of the comments used to imply that one of the checked*()
wrappers was missing checks, but that is not true because
the default implementation of forEachRemaining() delegates to
hasNext() and next(), which do have the checks. Only any
custom behavior implemented in the delegate's forEachRemaining()
is lost.

Bug: 35910877
Test: Treehugger.

Change-Id: If1c2c1057120f27cfc3180e501ab1b01e4b2117c