Add test to preserve behaviour

It's important to have ambiguity in these cases to introduce overload
 resolution by suspend-modifier without breaking changes in future

 Relates to #KT-23610

compiler/testData/diagnostics/tests/suspendConversion/overloadResolutionBySuspendModifier.txt

@@ -0,0 +1,8 @@
+package
+
+public fun foo(/*0*/ x: () -> kotlin.Int): kotlin.Unit
+public fun foo(/*0*/ x: suspend () -> kotlin.Int): kotlin.Unit
+public suspend fun suspendCall(): kotlin.Int
+public fun test1(): kotlin.Unit
+public fun test2(/*0*/ f: () -> kotlin.Int, /*1*/ g: suspend () -> kotlin.Int): kotlin.Unit
+public fun usualCall(): kotlin.Int