Add stronger checking

- Add assertions to enforce that objects are of the correct kind and
  have been allocated.

- Make destructors check if objects have been allocated before
  deleting.

- Operations that require a non-NullDevice return failure if given a
  NullDevice.

- Use static_cast rather than reinterpret_cast when cohersing from a
  base class to a derived class.

Change-Id: I02ee0ea9d7982fd7ca29d49c9b02cfae111b7127

rocclr/device/pal/palkernel.cpp

@@ -68,6 +68,9 @@ void HSAILKernel::setWorkGroupInfo(const uint32_t privateSegmentSize,
 }
 
 bool HSAILKernel::setKernelCode(amd::hsa::loader::Symbol* sym, amd_kernel_code_t* akc) {
+  if (prog().isNull()) {
+    return false;
+  }
   if (!sym) {
     return false;
   }