Revert "Revert "Add BacktraceOffline for offline backtracing.""

This reverts commit ab5e583327e4dfd9f7c38ab6ed4c4714508ce544.

And statically link llvm libraries on host to remove dependency
on 32-bit llvm shared library which is not included in the prebuilt.

Bug: 22229391

Change-Id: I8210687655ee1809fd820ab2a6ca5dfaf3f9096d
10 files changed