Revert "Remove Java 8 requirement."

This reverts commit e08a0e9ea5e2d57760e7195f8caa4e8a54ca09e5.

Reason for revert: broke androidx-master-dev build.
Exempt-From-Owner-Approval: A revert of a change breaking the build

Change-Id: I427d00087b9a33b36c6be0d3e119f44190bfed0b
1 file changed