Refactoring: move test folder out of "inline classes" folder

It was added there by mistake

compiler/testData/codegen/box/inlineClasses/funInterface/basicFunInterface.kt

@@ -1,15 +0,0 @@
-// !LANGUAGE: +FunctionInterfaceConversion
-
-fun interface Foo {
-    fun invoke(): String
-}
-
-class A : Foo {
-    override fun invoke(): String {
-        return "OK"
-    }
-}
-
-fun box(): String {
-    return A().invoke()
-}

compiler/testData/codegen/box/inlineClasses/funInterface/basicFunInterfaceConversion.kt

@@ -1,11 +0,0 @@
-// !LANGUAGE: +NewInference +FunctionInterfaceConversion +SamConversionPerArgument +SamConversionForKotlinFunctions
-
-fun interface Foo {
-    fun invoke(): String
-}
-
-fun foo(f: Foo) = f.invoke()
-
-fun box(): String {
-    return foo { "OK" }
-}