Merge "Revert "Revert "Add testHttpEngine_EnableHttpCache""" am: 21af035644

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2463195

Change-Id: I349f70a34fddb4523d0619f8ecddade5abad3e4c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>