[Java] Writer helper methods need to be applied to PromotableWriters

[jduo]

Describe the bug, including details regarding any error messages, version, and platform.

The new writer methods add in #37883 and #37791 need to be added to the PromotableWriter classes.

Additionally the writeToVarBinary and related methods should be renamed to writeVarBinary for consistency.

Component(s)

Java

[jduo]

take