removed AutoCastReceiver

check subtype for receiver by AutoCastUtils.isSubTypeByAutoCast directly
 #KT-4403 Fixed
 #KT-4415 Fixed

compiler/testData/diagnostics/tests/smartCasts/inference/kt4403.kt

@@ -0,0 +1,11 @@
+//KT-4403 Wrong "type mismatch" on smart cast with inference
+
+trait A
+trait B : A
+
+fun <T> T.f(): T = this
+
+fun test(a: A) {
+    if (a !is B) return
+    val <!UNUSED_VARIABLE!>c<!> = <!DEBUG_INFO_AUTOCAST!>a<!>.f() // type mismatch
+}