[automerger skipped] Merge "Rename mainline_system(.*).mk to...

[automerger skipped] Merge "Rename mainline_system(.*).mk to generic_system(.*).mk" am: 84b82254 am: df762465 -s ours am: e8affd9f -s ours

am skip reason: Change-Id I3609ec2d91b0f08859a36cac75c25876b1db6d6a with SHA-1 0116b6cb is in history

Original change: https://android-review.googlesource.com/c/platform/build/+/1396210

Change-Id: I0cb03eb2fecb5a04ad781f466ec468c510c885c4