[clang][bytecode] Use IsNonNull op in visitBool() (#139846)

We don't need to emit the nullptr and compare to it anymore.

Author: tbaederr

clang/lib/AST/ByteCode/Compiler.cpp

@@ -4107,11 +4107,8 @@ template <class Emitter> bool Compiler<Emitter>::visitBool(const Expr *E) {
     return true;
 
   // Convert pointers to bool.
-  if (T == PT_Ptr) {
-    if (!this->emitNull(*T, 0, nullptr, E))
-      return false;
-    return this->emitNE(*T, E);
-  }
+  if (T == PT_Ptr)
+    return this->emitIsNonNullPtr(E);
 
   // Or Floats.
   if (T == PT_Float)