[class] Remove unncessary check for private field

A computed property can never be a private field. That's a SyntaxError.

Change the check to a DCHECK.

Bug: v8:5368
Change-Id: I6701b60f3193639f3ccffacda25074d32d5de5b8
Reviewed-on: https://chromium-review.googlesource.com/c/1385267Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58451}

src/interpreter/bytecode-generator.cc

@@ -1866,8 +1866,6 @@ void BytecodeGenerator::BuildClassLiteral(ClassLiteral* expr, Register name) {
     for (int i = 0; i < expr->properties()->length(); i++) {
       ClassLiteral::Property* property = expr->properties()->at(i);
       if (property->is_computed_name()) {
-        DCHECK_IMPLIES(property->kind() == ClassLiteral::Property::FIELD,
-                       !property->is_private());
         Register key = register_allocator()->GrowRegisterList(&args);
 
         builder()->SetExpressionAsStatementPosition(property->key());
@@ -1889,8 +1887,8 @@ void BytecodeGenerator::BuildClassLiteral(ClassLiteral* expr, Register name) {
               .Bind(&done);
         }
 
-        if (property->kind() == ClassLiteral::Property::FIELD &&
-            !property->is_private()) {
+        if (property->kind() == ClassLiteral::Property::FIELD) {
+          DCHECK(!property->is_private());
           // Initialize field's name variable with the computed name.
           DCHECK_NOT_NULL(property->computed_name_var());
           builder()->LoadAccumulatorWithRegister(key);