Use a different lock for the ProcessStatsService

...instead of the global AMS, as it involves disk I/O

Bug: 162425754
Test: atest ProcStatsValidationTests
Test: atest ProcessStatsDumpsysTest
Test: atest CtsIncidentHostTestCases:ProcStatsProtoTest
Change-Id: Iad144097b9fbab3ab7b5506c9baf0ca0142db6d4
6 files changed