Also add the missing `.size` directives to all the assembler functions
for slightly improved backtraces.
Test: crasher64 pac; crasher64 bti
Change-Id: I8e0c127cbff56c33637e6ca8f1d927b971951807
Remove debuggerd in favor of a helper process that gets execed by
crashing processes.
Bug: http://b/30705528
Test: debuggerd_test
Change-Id: I9906c69473989cbf7fe5ea6cccf9a9c563d75906