PSI2IR fix suspend conversion tests

- support chained suspend conversion + SAM conversion
- support suspend conversion in vararg elements

compiler/testData/codegen/box/suspendConversion/suspendConversionWithFunInterfaces.kt

@@ -1,6 +1,7 @@
 // FIR_IDENTICAL
 // !LANGUAGE: +SuspendConversion
 // !DIAGNOSTICS: -UNUSED_PARAMETER
+// IGNORE_BACKEND: JVM
 
 fun interface SuspendRunnable {
     suspend fun invoke()
@@ -17,8 +18,7 @@ suspend fun bar3(s: String = ""): Int = 0
 fun box(): String {
     foo1(::bar1)
     foo1(::bar2)
-
-    foo1(::bar3) // Should be ambiguity
+    foo1(::bar3)
 
     return "OK"
 }