Create two sentinel api levels

This relands aosp/2470068. The original CL was submitted as part of a
stack that broke tm and udc. Those branches still contain soong modules
with min_sdk_version of type (kind+level).

Test: m nothing on tm and udc (via go/abtd)
Bug: 208456999

Change-Id: I8e013ec10530372f70f0ab0505b7eebeee2b360b