[automerger skipped] Move mSessionKey into Ikev2VpnRunner and make it to be a...

[automerger skipped] Move mSessionKey into Ikev2VpnRunner and make it to be a final var am: 700a5289 -s ours am: b3129371 -s ours am: c479fda5 -s ours

am skip reason: Merged-In If7eb7e0ec8ab42b17a5636aeced65385e7849b6a with SHA-1 1cb9f618 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/18115171



Change-Id: I29b86b42d986522f0fe6fadd678c31322cfb65df
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>