Set memlock rlimit to 64KB

Defaulting Android to limit memlock to 64KB. This will help preventing
pages from being swapped until the app is killed it's memory will stay
resident. CTS test is enforced only in U+ devies.

Bug: 201797650
Test: Added new test to verify we are memlock at or under 64KB
Change-Id: I5a9e9da12f6df5a056ee47d0593c13e9c779e054