update Java references to file class when a file is renamed

compiler/frontend.java/src/org/jetbrains/kotlin/load/kotlin/PackagePartClassUtils.kt

@@ -36,7 +36,7 @@ public object PackagePartClassUtils {
 
     private val PART_CLASS_NAME_SUFFIX = "Kt"
 
-    private @JvmStatic fun getPartClassName(str: String): String =
+    public @JvmStatic fun getPartClassName(str: String): String =
             if (str.isEmpty())
                 "_$PART_CLASS_NAME_SUFFIX"
             else

compiler/light-classes/src/org/jetbrains/kotlin/asJava/KotlinLightClassForFacade.kt

@@ -180,6 +180,8 @@ public class KotlinLightClassForFacade private constructor(
 
     override fun getName() = facadeClassFqName.shortName().asString()
 
+    override fun setName(name: String): PsiElement? = this
+
     override fun getQualifiedName() = facadeClassFqName.asString()
 
     override fun isValid() = files.all { it.isValid() }