PSI2IR: SAM conversion should be performed once for index variables

Given esoteric code as in 'caoWithAdaptationForSam.kt', we should make
sure that we pass same objects to 'get' and 'set'.

compiler/testData/ir/irText/expressions/callableReferences/caoWithAdaptationForSam.kt

@@ -0,0 +1,47 @@
+// !LANGUAGE: +NewInference +FunctionReferenceWithDefaultValueAsOtherType +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+
+fun interface IFoo {
+    fun foo(i: Int)
+}
+
+fun interface IFoo2 : IFoo
+
+object A
+object B
+
+operator fun A.get(i: IFoo) = 1
+operator fun A.set(i: IFoo, newValue: Int) {}
+
+operator fun B.get(i: IFoo) = 1
+operator fun B.set(i: IFoo2, newValue: Int) {}
+
+fun withVararg(vararg xs: Int) = 42
+
+fun test1() {
+    A[::withVararg] += 1
+}
+
+fun test2() {
+    B[::withVararg] += 1
+}
+
+fun test3(fn: (Int) -> Unit) {
+    A[fn] += 1
+}
+
+fun test4(fn: (Int) -> Unit) {
+    if (fn is IFoo) {
+        A[fn] += 1
+    }
+}
+
+fun test5(a: Any) {
+    a as (Int) -> Unit
+    A[a] += 1
+}
+
+fun test6(a: Any) {
+    a as (Int) -> Unit
+    a as IFoo
+    A[a] += 1
+}