[libomptarget][amdgpu] Convert an assert to print and offload_fail

[JonChesterfield]

Summary

[libomptarget][amdgpu] Convert an assert to print and offload_fail

The kernel launched is supposed to be present in the binary, but a not yet
diagnosed bug means it is missing for some of the qmcpack test cases. Changing
from assert to print and offload_fail should help diagnose that and similar bugs.

[jdoerfert]

LG

openmp/libomptarget/plugins/amdgpu/src/rtl.cpp

for (int32_t i = 0; i < arg_num; ++i) {
     ptrs[i] = (void *)((intptr_t)tgt_args[i] + tgt_offsets[i]);
     args[i] = &ptrs[i];
     DP("Offseted base: arg[%d]:" DPxMOD "\n", i, DPxPTR(ptrs[i]));
   }
 
   KernelTy *KernelInfo = (KernelTy *)tgt_entry_ptr;
 
   std::string kernel_name = std::string(KernelInfo->Name);
+  if (KernelInfoTable[device_id].find(kernel_name) ==
+      KernelInfoTable[device_id].end()) {
+    DP("Kernel %s not found\n", kernel_name.c_str());
+    return OFFLOAD_FAIL;
+  }
+
   uint32_t sgpr_count, vgpr_count, sgpr_spill_count, vgpr_spill_count;
 
   {
-    assert(KernelInfoTable[device_id].find(kernel_name) !=
-           KernelInfoTable[device_id].end());
     auto it = KernelInfoTable[device_id][kernel_name];
     sgpr_count = it.sgpr_count;
     vgpr_count = it.vgpr_count;
     sgpr_spill_count = it.sgpr_spill_count;
     vgpr_spill_count = it.vgpr_spill_count;
   }
 
   /*
// Run on the device.
     packet->private_segment_size = 0;
     packet->group_segment_size = 0;
     packet->kernel_object = 0;
     packet->kernarg_address = 0;     // use the block allocator
     packet->reserved2 = 0;           // atmi writes id_ here
     packet->completion_signal = {0}; // may want a pool of signals
 
     {
-      assert(KernelInfoTable[device_id].find(kernel_name) !=
-             KernelInfoTable[device_id].end());
       auto it = KernelInfoTable[device_id][kernel_name];
       packet->kernel_object = it.kernel_object;
       packet->private_segment_size = it.private_segment_size;
       packet->group_segment_size = it.group_segment_size;
       assert(arg_num == (int)it.num_args);
     }
 
     KernelArgPool *ArgPool = nullptr;