Bug: 37916906
Test: Builds 'n' boots.
Change-Id: Ia1d86264446ebecc1ca79f32f11354921bc77668
Merged-In: I208ec6a864127a059fb389417a9c6b259d7474cb

The following commits were cherry-picked from internal master to AOSP,
but to avoid merge-conflicts we'll do a large diff instead of individual
cherry-picks:
521742e9
9aefc916
3686efca
de51e7de
fff3fe2f

Bug: 37916906
Test: angler builds and boots.
Merged-In: Ie010cc12ae866dbb97c387471f433158d3b699f3
Change-Id: I5126ebe88b9c76a74690ecf95851d389cfc22d1f

Add /dev/kmsg_debug on userdebug devices, to allow crash_dump to log
crashes to dmesg when logd isn't up yet (or is the one crashing).

(Originally commited in a015186f)
(cherry-pick of commit: 3458ec13)

Bug: 37916906
Bug: 36574794
Bug: 62101480
Test: Builds and boots.
Change-Id: I83aa392f49bb412d96534925fb02921a8f4731fa

(cherry-pick of commit: 55c77504)

Bug: 37916906
Bug: 37896931
Test: none, just prebuilt update.
Change-Id: I55b5179f98703026699a59cce4b2e1afb166fd1d

More changes went into oc-dev after the freeze-date.  Reflect them.
(cherry-pick of commit: 148578a6)

Bug: 37916906
Bug: 37896931
Test: prebuilts - none.
Change-Id: I3300751ea7362d5d96b327138544be65eb9fc483

commit: 5c6a227e added the oc-dev
sepolicy prebuilts (api 26.0), but did not include the corresponding
base mapping file, which is to be maintained along with current
platform development in order to ensure backwards compatibility.
(cherry-pick of commit: 5e4e0d7f)

Bug: 37916906
Bug: 37896931
Test: none, this just copies the old mapping file to prebuilts.
Change-Id: Ia5c36ddab036352845878178fa9c6a9d649d238f

Copy the final system sepolicy from oc-dev to its prebuilt dir
corresponding to its version (26.0) so that we can uprev policy and
start maintaining compatibility files, as well as use it for CTS
tests targeting future platforms.

(cherry-pick of commit: 5c6a227e)

Bug: 37896931
Bug: 37916906
Test: none, this just copies the old policy.
Change-Id: Ib069d505e42595c467e5d1164fb16fcb0286ab93

Copy the final system sepolicy from oc-dev to its prebuilt dir
corresponding to its version (26.0) so that we can uprev policy and
start maintaining compatibility files, as well as use it for CTS
tests targeting future platforms.

Bug: 37896931
Test: none, this just copies the old policy.
Change-Id: Ib069d505e42595c467e5d1164fb16fcb0286ab93