[FIR-TEST] Add new testdata generated after changes in previous commit

compiler/testData/diagnostics/testsWithStdLib/cast/AsInsideIn.fir.kt

@@ -0,0 +1,21 @@
+// !WITH_NEW_INFERENCE
+// See also KT-10386
+interface A
+class B : A
+fun foo1(list: List<A>, arg: B?): Boolean {
+    // Type mismatch
+    return arg in list // resolved to extension
+}
+fun foo2(list: List<A>, arg: B?): Boolean {
+    // FAKE: no cast needed
+    return arg as A? in list
+}
+fun foo3(list: List<A>, arg: B?): Boolean {
+    // No warning but KNPE risk
+    return arg!! in list
+}
+// But
+fun foo4(list: List<A>, arg: B): Boolean {
+    // Ok
+    return arg in list
+}