Remove backend tests on old inference

Also remove any mentions of NewInference, and rename some tests.

compiler/testData/codegen/box/funInterface/partialSam.kt

@@ -1,4 +1,3 @@
-// !LANGUAGE: +NewInference +FunctionalInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
 // WITH_RUNTIME
 
 fun interface Fn<T, R> {
@@ -38,4 +37,4 @@ fun box(): String {
     if (x != "LFoo42239 Bar1LFoo Foo42239 LBar1Foo") return x
 
     return "OK"
-}
+}