Change Signature: Substitute new function name into generated this-expressions

#KT-7920 Fixed

idea/src/org/jetbrains/kotlin/idea/refactoring/changeSignature/usages/JetParameterUsage.kt

@@ -56,7 +56,7 @@ public class JetParameterUsage(
     override fun getReplacementText(changeInfo: JetChangeInfo): String =
             if (changeInfo.receiverParameterInfo != parameterInfo) {
                 parameterInfo.getInheritedName(containingFunction)
-            } else "this@${containingFunction.getOriginalFunctionDescriptor().getName().asString()}"
+            } else "this@${changeInfo.getNewName()}"
 }
 
 public class JetNonQualifiedOuterThisUsage(

idea/testData/refactoring/changeSignature/ConvertToExtensionAndRenameAfter.kt

@@ -0,0 +1,5 @@
+class C {
+    fun String.foo1() {
+        print(this)
+    }
+}

idea/testData/refactoring/changeSignature/ConvertToExtensionAndRenameBefore.kt

@@ -0,0 +1,5 @@
+class C {
+    fun <caret>foo(p: String) {
+        print(p)
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/changeSignature/JetChangeSignatureTest.java

@@ -772,7 +772,8 @@ public class JetChangeSignatureTest extends KotlinCodeInsightTestCase {
         JetPsiFactory psiFactory = new JetPsiFactory(getProject());
         changeInfo.addParameter(
                 new JetParameterInfo(changeInfo.getMethodDescriptor().getBaseDescriptor(),
-                                     -1, "s", KotlinBuiltIns.getInstance().getStringType(), null, psiFactory.createExpression("\"foo\""), JetValVar.None, null));
+                                     -1, "s", KotlinBuiltIns.getInstance().getStringType(), null, psiFactory.createExpression("\"foo\""),
+                                     JetValVar.None, null));
         doTest(changeInfo);
     }
 
@@ -910,6 +911,13 @@ public class JetChangeSignatureTest extends KotlinCodeInsightTestCase {
         doTest(changeInfo);
     }
 
+    public void testConvertToExtensionAndRename() throws Exception {
+        JetChangeInfo changeInfo = getChangeInfo();
+        changeInfo.setReceiverParameterInfo(changeInfo.getNewParameters()[0]);
+        changeInfo.setNewName("foo1");
+        doTest(changeInfo);
+    }
+
     @NotNull
     @Override
     protected String getTestDataPath() {