Merge "Attempt to clear memory after keyguard PIN entry" into sc-dev am: f16b3f76aa am: e0f027aff9 am: c8cfcbcb9d

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/15502355

Change-Id: Iaf5cb101a7a0573044703d6fa84ac002b9bf346d