IR: 'fun interface' support

compiler/testData/ir/irText/expressions/funInterface/partialSam.kt

@@ -0,0 +1,28 @@
+// !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+// TARGET_BACKEND: JVM
+// IGNORE_BACKEND: JVM_IR
+// IGNORE_BACKEND_FIR: JVM_IR
+// WITH_RUNTIME
+
+fun interface Fn<T, R> {
+    fun run(s: String, i: Int, t: T): R
+}
+
+class J {
+    fun runConversion(f1: Fn<String, Int>, f2: Fn<Int, String>): Int {
+        return f1.run("Bar", 1, f2.run("Foo", 42, 239))
+    }
+}
+
+val fsi = object : Fn<String, Int> {
+    override fun run(s: String, i: Int, t: String): Int = 1
+}
+
+val fis = object : Fn<Int, String> {
+    override fun run(s: String, i: Int, t: Int): String = ""
+}
+
+fun test(j: J) {
+    j.runConversion(fsi) { s, i, ti -> ""}
+    j.runConversion({ s, i, ts -> 1 }, fis)
+}