Enable GDA+IPC (#249)

* Enable GDA+IPC
Fix ROCSHMEM_DISABLE_IPC for both RO and GDA

* add more functionality to bootstrap class

we need a few more functions in the boostrap class to be able to fully
handle the rocshmem requirements:
 - add a function to return the list of local ranks
 - provide a groupAllgather operation which takes a vector of ranks
   participating
 - provide a groupAlltoall operation which takes a vector of ranks
   participating

Also, update the functionality of the gda-Alltoall and gda-Allreduce
operations to take advantage of these functions.

* ipc_policy adapted to use bootstrap groupallgather

* bugfix: there was a mistake in computing sendto in groupallgather

* bugfix: shm_size and shm_rank were set in a local variable rather than
the class member

* mpi-bootstrap: remove an unecessary allgather

---------

Co-authored-by: Edgar Gabriel <Edgar.Gabriel@amd.com>

src/util.cpp

@@ -127,9 +127,14 @@ void rocm_memory_lock_to_fine_grain(void* ptr, size_t size, void** gpu_ptr,
 rocshmem_env_config::rocshmem_env_config() {
   char* env_value = NULL;
 
+  env_value = getenv("ROCSHMEM_DISABLE_IPC");
+  if (NULL != env_value) {
+    disable_ipc = atoi(env_value);
+  }
+  // For backward compatibility, synonymous with ROCSHMEM_DISABLE_IPC
   env_value = getenv("ROCSHMEM_RO_DISABLE_IPC");
   if (NULL != env_value) {
-    ro_disable_ipc = atoi(env_value);
+    disable_ipc = atoi(env_value);
   }
 
   env_value = getenv("ROCSHMEM_RO_PROGRESS_DELAY");
@@ -163,8 +168,8 @@ rocshmem_env_config::rocshmem_env_config() {
   }
 }
 
-int rocshmem_env_config::get_ro_disable_ipc() {
-  return ro_disable_ipc;
+int rocshmem_env_config::get_disable_ipc() {
+  return disable_ipc;
 }
 
 int rocshmem_env_config::get_ro_progress_delay() {