Support SAM conversion in psi2ir

SAM conversion takes a function value (function type or a subtype),
and produces a SAM interface value.

compiler/testData/ir/irText/expressions/sam/samConversions.kt

@@ -0,0 +1,31 @@
+// WITH_JDK
+// FILE: samConversions.kt
+fun J.test0(a: Runnable) {
+    J.runStatic(a)
+    runIt(a)
+}
+
+fun test1() {
+    J.runStatic { test1() }
+}
+
+fun J.test2() {
+    runIt { test1() }
+}
+
+fun J.test3(a: () -> Unit) {
+    run2(a, a)
+}
+
+fun J.test4(a: () -> Unit, b: () -> Unit, flag: Boolean) {
+    runIt(if (flag) a else b)
+}
+
+// FILE: J.java
+public class J {
+    public static void runStatic(Runnable r) {}
+
+    public void runIt(Runnable r) {}
+
+    public void run2(Runnable r1, Runnable r2) {}
+}