clean up removal warnings from build

With the new javac removal warnings enabled, there are approximately 350 new warnings introduced into the build. These are temporarily disabled through the use of the -Xlint:-removal flag. The warnings should be cleared, and then this flag should be removed from the makefiles.

This is an umbrella bug that will contain subtasks for fixing each area.

In most cases, the right way to deal with the warning is to add @SuppressWarnings("removal") at an appropriate place near the warning.