Bug 1763103 - Part 4: Only initialise home object for private instance accessors when neeeded. r=arai

Private instance accessors were always initialising the home object, even when
`needsHomeObject()` was `false`.

Depends on D142931

Differential Revision: https://phabricator.services.mozilla.com/D142932

js/src/frontend/BytecodeEmitter.cpp

@@ -9862,11 +9862,13 @@ bool BytecodeEmitter::emitPrivateMethodInitializers(ClassEmitter& ce,
     }
     // The private method body needs to access the home object,
     // and the CE knows where that is on the stack.
-    if (!ce.emitMemberInitializerHomeObject(false)) {
-      //            [stack] HOMEOBJ HERITAGE? ARRAY METHOD
-      // or:
-      //            [stack] CTOR HOMEOBJ ARRAY METHOD
-      return false;
+    if (classMethod->method().funbox()->needsHomeObject()) {
+      if (!ce.emitMemberInitializerHomeObject(false)) {
+        //          [stack] HOMEOBJ HERITAGE? ARRAY METHOD
+        // or:
+        //          [stack] CTOR HOMEOBJ ARRAY METHOD
+        return false;
+      }
     }
     if (!emitLexicalInitialization(storedMethodAtom)) {
       //            [stack] HOMEOBJ HERITAGE? ARRAY METHOD