Drop AndroidX dependency

Cronet in AOSP doesn't require AndroidX. The only remaning use of
AndroidX upstream is BuildCompat#isAtLeastT, but here that makes use of
SdkLevel#isAtLeastT.

Test: ./update_result.sh && m
Change-Id: I46634e62f875072347b21235a695ebca6b03e3b5
1 file changed