Merge "Attempt to clear memory after keyguard PIN entry" into sc-dev am: f16b3f76 am: abd75290 am: 44ed3ed9 am: 5c202c7f

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

Change-Id: I59d501e8bafda0dcdc0f8e7cd0bff90a9cb00627