Merge "Revert "Revert "Add testHttpEngine_EnableHttpCache""" am: 21af035644 am: 76260a9d89

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

Change-Id: I09e3e9658a5c18beec1466c35b8a123c4711d495
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>