transcoding: fixes for binder died handling

Change client id type to uintptr_t counter, instead of
casting binder to int64_t.

Save all shared_ptrs of clients in global registry.

bug: 154734285
bug: 145233472

test: transcoding unit tests; manually plant crash
in test client and check binderDied handling in log.
Change-Id: If6523a1c6b7ce797a2201462399174e9cf0a3c71

Change-Id: I6b312c0f28a345285e27b738c37baee2bccae755