Support member extension properties, implement KClass.getExtensionProperties()

#KT-6570 Fixed

compiler/testData/codegen/boxWithStdlib/reflection/methodsFromAny/memberExtensionToString.kt

@@ -0,0 +1,12 @@
+import kotlin.reflect.jvm.kotlin
+
+class A {
+    var String.id: String
+        get() = this
+        set(value) {}
+}
+
+fun box(): String {
+    val p = javaClass<A>().kotlin.getExtensionProperties().single()
+    return if ("$p" == "var A.(kotlin.String.)id") "OK" else "Fail $p"
+}