Refactor RO backend data structures (#49)

- Remove hdp and ipc pointers from BlockHandle, align RO stats with RO contexts

- Add run commands for `rocshmem_g` and `rocshmem_p` API tests in driver.sh

- Allocate rocshmem API return buffers based on number of device contexts.

- Associate status flag address with blocking calls and remove threadId dependency
   - Associated the status flag address with each blocking call request to notify the GPU thread.
   - Removed dependency on threadId for determining the appropriate status flag index.

- Move status flag buffer allocation to backend.

- Initialize allocated memeory to zero

[ROCm/rocshmem commit: df4ad2c04d]

projects/rocshmem/src/device_proxy.hpp

@@ -51,7 +51,7 @@ class DeviceProxy {
     /*
      * Default memory provided by the allocation to recognizable bytes.
      */
-    memset(static_cast<void*>(temp), 0xBC, size_bytes);
+    memset(static_cast<void*>(temp), 0, size_bytes);
 
     /*
      * Pass the memory into a unique ptr for tracking.