Add host APIs for querying device ctx and remote heap pointer (#200)

* Add host APIs for querying device ctx and remote heap pointer

* Host API to query device pointer for ROCSHMEM_DEFAULT_CONTEXT,
  this is needed to support dynamic module initialization via device kernel
  library bitcode.
* Host API to query remote symmetric heap pointer that can be used in
  custom device kernel for RMA operations.

* Added rocshmem_ptr implementation within the Host Context class
* Enables pointer retrieval functionality for symmetric data objects
* Copy IPC pointers to host memory in RO host context

---------

Co-authored-by: avinashkethineedi <avinash.kethineedi@amd.com>

src/context_host.cpp

@@ -31,7 +31,11 @@ namespace rocshmem {
 __host__ Context::Context(Backend* handle, bool shareable)
     : num_pes(handle->getNumPEs()),
       my_pe(handle->getMyPE()),
-      fence_(shareable) {}
+      fence_(shareable) {
+}
+
+__host__ Context::~Context() {
+}
 
 /******************************************************************************
  ********************** CONTEXT DISPATCH IMPLEMENTATIONS **********************
@@ -93,6 +97,12 @@ __host__ void Context::quiet() {
   HOST_DISPATCH(quiet());
 }
 
+__host__ void* Context::shmem_ptr(const void* dest, int pe) {
+  ctxHostStats.incStat(NUM_HOST_SHMEM_PTR);
+
+  HOST_DISPATCH_RET_PTR(shmem_ptr(dest, pe));
+}
+
 __host__ void Context::sync_all() {
   ctxHostStats.incStat(NUM_HOST_SYNC_ALL);