Revert "Objects.firstNonNull() moved to MoreObjects"

This reverts commit aaad55220fffffcd8c6d611bd7b2b438f0f41fca.
Revert "Objects.toStringHelper() moved to MoreObjects"

This reverts commit 3abb0548406b0026cca4262b27df19a4a66a312b.
Update CHANGES