Call chains: receiver data flow info is dropped for extensions with nullable receiver #KT-10056 Fixed

compiler/testData/diagnostics/tests/smartCasts/safecalls/nullableReceiverWithFlexible.txt

@@ -0,0 +1,15 @@
+package
+
+public fun test(): kotlin.Unit
+public inline fun </*0*/ T, /*1*/ R> T.let(/*0*/ f: (T) -> R): R
+
+public open class Foo {
+    private constructor Foo(/*0*/ bar: kotlin.String!)
+    public final var bar: kotlin.String!
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    // Static members
+    public open fun create(/*0*/ bar: kotlin.String!): Foo!
+}