GDBServer: Preserve unchanged resume state

Avoid calling SetPC when an address-qualified continue or single-step
names the CPU's current PC. The next instruction is already prefetched
at that address, and rebuilding the pipeline would incorrectly discard
pending load and branch-delay state.

src/core/gdb_server.cpp

@@ -316,7 +316,7 @@ bool GDBServer::Cmd$c(ClientSocket* client, std::string_view data)
   }
 
   client->SendAck();
-  if (address.has_value())
+  if (address.has_value() && address.value() != CPU::g_state.pc)
     CPU::SetPC(address.value());
   System::PauseSystem(false);
   return true;
@@ -334,7 +334,7 @@ bool GDBServer::Cmd$s(ClientSocket* client, std::string_view data)
   }
 
   client->SendAck();
-  if (address.has_value())
+  if (address.has_value() && address.value() != CPU::g_state.pc)
     CPU::SetPC(address.value());
   System::SingleStepCPU();
   return true;