revive probe mode container case

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on September 30, 2013 11:57:18_

DR has long had hotpatching support that operates both with and without the
code cache. Turning that into a nice API for users to write probes was
never completed, however.

Xref https://code.google.com/p/drmemory/wiki/Projects#Probe_mode We made a new interface dr_register_probes() that supports raw addresses,
library offsets, or exported functions, but it is not completely finished.

For example, currently you can only call dr_register_probes() once, during
DR init. We'd like to support it being called at any time. The code
implies that we need to use an internal nudge if it's called later, though
we should revisit that.

Some issues mentioned in the code:

Old PR Issue
225548 Probe API: define status codes
225550 Probe API: generate unique probe id
225578 Probe API: implement internal nudge for dr_register_probes()
225580 Probe API: support multiple calls to dr_register_probes()
225654 Probe API: implement support for exported functions
225658 Probe API: implement support for raw virtual address probes and callbacks
225663 Probe API: validate probe definition upon registration
226578 Probe API: dr_register_probes should flush incompatible pcaches during both init and nudge => issue #660 229881 Probe API: probes return status codes and actions NYI
275129 Probe API sample
533384 Probe API: dr_register_probes() needs to return a success status

_Original issue: http://code.google.com/p/dynamorio/issues/detail?id=1281_