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/withAdaptationForSam.kt

@@ -0,0 +1,20 @@
+// !LANGUAGE: +NewInference +FunctionReferenceWithDefaultValueAsOtherType +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
+
+fun interface IFoo {
+    fun foo(i: Int)
+}
+
+fun useFoo(foo: IFoo) {}
+
+fun useVarargFoo(vararg foos: IFoo) {}
+
+fun withVararg(vararg xs: Int) = 42
+
+fun test() {
+    useFoo(::withVararg)
+}
+
+// TODO
+//fun testVarargOfSams() {
+//    useVarargFoo(::withVararg)
+//}