Merge "Revert "Refine documentation for Process.setThreadPriority"" am: fe6160ab9c am: 1cb565ec3c am: 017adb4085

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1440031

Change-Id: Ib3da013ce94288729a2b2d177fcc4d2345e1af58