[dynarmic] Fix missing return after exception handling

Restores return statement that was removed in commit 21cd44ec04.
Without the return, exceptions would fall through causing undefined behavior
and null pointer crashes.

Fixes possible 'Pokemon Legends: Z-A' 0 fps freeze on startup.

src/core/arm/dynarmic/arm_dynarmic_64.cpp

@@ -145,9 +145,11 @@ public:
         default:
             if (m_debugger_enabled) {
                 ReturnException(pc, InstructionBreakpoint);
+                return;
             } else {
                 m_parent.LogBacktrace(m_process);
                 LOG_CRITICAL(Core_ARM, "ExceptionRaised(exception = {}, pc = {:08X}, code = {:08X})", static_cast<std::size_t>(exception), pc, m_memory.Read32(pc));
+                return;
             }
         }
     }