Merge changes I51a58e57,Ibdf8c2c5,I0b1e9221,Ie2a62c5a,Ic7fab603, ...

* changes:
  GPU Memory: add errno to error log messages
  GPU Memory: update unittest to reduce flakiness
  GpuMem: refactor and add unittest for traverseGpuMemTotals
  GpuMemTracer: remove the sleep workaround
  GPU Memory: remove an infeasible TODO
  GpuMem perfetto producer
  GPU Memory: ensure bpf program is attached to the tracepoint
  GpuMem: fix flaky unittests on cuttlefish platform
  GPU Memory: add unittests for libgpumem
  GPU Memory: install gpu_mem.o and integrate libgpumem
  GPU Memory: implement libgpumem to interact with bpf
  GPU Memory: add bpf c program for gpu_mem/gpu_mem_total tracepoint