MIPS: [es6] Throw TypeError for computed static prototype property name

Port 8d946b9c

Original commit message:
The prototype of a class constructor function is read only. When we set
computed property names we were ignoring this and we were overriding the
property.

Since the prototype is the only possible own read only property on the
constructor function object we special case this so we do not have to
check this for every property in the class literal.

BUG=v8:3945
LOG=N

Review URL: https://codereview.chromium.org/993963003

Cr-Commit-Position: refs/heads/master@{#27119}

src/mips/full-codegen-mips.cc

@@ -2562,6 +2562,16 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit) {
     }
     __ push(scratch);
     EmitPropertyKey(property, lit->GetIdForProperty(i));
+
+    // The static prototype property is read only. We handle the non computed
+    // property name case in the parser. Since this is the only case where we
+    // need to check for an own read only property we special case this so we do
+    // not need to do this for every property.
+    if (property->is_static() && property->is_computed_name()) {
+      __ CallRuntime(Runtime::kThrowIfStaticPrototype, 1);
+      __ push(v0);
+    }
+
     VisitForStackValue(value);
     EmitSetHomeObjectIfNeeded(value, 2);
 

src/mips64/full-codegen-mips64.cc

@@ -2560,6 +2560,16 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit) {
     }
     __ push(scratch);
     EmitPropertyKey(property, lit->GetIdForProperty(i));
+
+    // The static prototype property is read only. We handle the non computed
+    // property name case in the parser. Since this is the only case where we
+    // need to check for an own read only property we special case this so we do
+    // not need to do this for every property.
+    if (property->is_static() && property->is_computed_name()) {
+      __ CallRuntime(Runtime::kThrowIfStaticPrototype, 1);
+      __ push(v0);
+    }
+
     VisitForStackValue(value);
     EmitSetHomeObjectIfNeeded(value, 2);