copy of org.jetbrains.kotlin.js.descriptorUtils.nameIfStandardType for translator needs

experiments/student-backend/src/org/jetbrains/kotlin/student/descriptorUtils.kt

@@ -0,0 +1,20 @@
+package org.jetbrains.kotlin.student.descriptorUtils
+
+import org.jetbrains.kotlin.descriptors.PackageFragmentDescriptor
+import org.jetbrains.kotlin.name.Name
+import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
+import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.utils.addToStdlib.check
+
+/**
+ * Created by minamoto on 17/09/2016.
+ * this code is copied from org.jetbrains.kotlin.js.descriptorUtils
+ */
+val KotlinType.nameIfStandardType: Name?
+    get() {
+        return constructor.declarationDescriptor
+                ?.check { descriptor ->
+                    descriptor.builtIns.isBuiltInPackageFragment(descriptor.containingDeclaration as? PackageFragmentDescriptor)
+                }
+                ?.name
+    }