Psi2Ir: fix usage of flexible vararg type after approximation

This only affects JVM IR, and this is similar to how this was done in
the old JVM backend in `CallBasedArgumentGenerator.generateVararg`.

 #KT-52146 Fixed

compiler/testData/codegen/box/vararg/kt52146_samWithSelfTypeAndStarProjection.kt

@@ -0,0 +1,27 @@
+// TARGET_BACKEND: JVM
+// FULL_JDK
+// JVM_TARGET: 1.8
+// FILE: J.java
+
+import java.util.function.*;
+
+public class J<SELF extends J<SELF, ACTUAL>, ACTUAL> {
+    public final SELF satisfies(Consumer<? super ACTUAL>... c) {
+        return null;
+    }
+}
+
+// FILE: box.kt
+
+import java.util.function.*
+
+fun test(j: J<*, *>) {
+    j.satisfies(Consumer { it is CharSequence })
+    j.satisfies({ it is CharSequence })
+}
+
+fun box(): String {
+    class K : J<K, String>()
+    test(K())
+    return "OK"
+}