Add tests for obsolete issues (KT-42722, KT-39880)

compiler/testData/codegen/box/operatorConventions/kt39880.kt

@@ -0,0 +1,10 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WITH_RUNTIME
+
+fun foo(fn: () -> Boolean) {}
+
+fun box(): String {
+    foo { 1 in setOf("1") }
+    val a = 1 in setOf("1")
+    return "OK"
+}

compiler/testData/codegen/box/operatorConventions/kt42722.kt

@@ -0,0 +1,10 @@
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WITH_RUNTIME
+
+fun box(): String {
+    val set = setOf<Int>(1, 2, 3, 4, 5)
+    println(0 in set)
+    println(1 in set)
+    println(null in set)
+    return "OK"
+}