FIR Java: support Kotlin extension overriding: at last, #KT-29937 Fixed

idea/testData/fir/multiModule/javaInheritsKotlinExtension/extraDump.java.txt

@@ -0,0 +1,4 @@
+public open class Inheritor : R|Second| {
+    public open operator function foo R|First|.(first: R|kotlin/String|, s: R|kotlin/Int|): R|kotlin/Unit|
+
+}

idea/testData/fir/multiModule/javaInheritsKotlinExtension/jvm/Base.kt

@@ -0,0 +1,5 @@
+interface First
+
+open class Second {
+    open fun First.foo(s: String, i: Int) {}
+}

idea/testData/fir/multiModule/javaInheritsKotlinExtension/jvm/Base.txt

@@ -0,0 +1,10 @@
+FILE: Base.kt
+    public abstract interface First {
+    }
+    public open class Second {
+        public constructor(): super<R|kotlin/Any|>()
+
+        public open function foo R|First|.(s: R|kotlin/String|, i: R|kotlin/Int|): R|kotlin/Unit| {
+        }
+
+    }

idea/testData/fir/multiModule/javaInheritsKotlinExtension/jvm/Inheritor.java

@@ -0,0 +1,3 @@
+public class Inheritor extends Second {
+    public void foo(First first, String s, int i) {}
+}

idea/testData/fir/multiModule/javaInheritsKotlinExtension/jvm/Test.kt

@@ -0,0 +1,5 @@
+class Tester : Inheritor(), First {
+    fun test() {
+        foo("abc", 456)
+    }
+}

idea/testData/fir/multiModule/javaInheritsKotlinExtension/jvm/Test.txt

@@ -0,0 +1,9 @@
+FILE: Test.kt
+    public final class Tester : R|Inheritor|, R|First| {
+        public constructor(): super<R|Inheritor|>()
+
+        public final function test(): R|kotlin/Unit| {
+            R|/Inheritor.foo|(String(abc), Int(456))
+        }
+
+    }