Add some tests on adapted references with varargs and reflection

Also rename "varargAndDefaults" test directory to "adaptedReferences"

compiler/testData/codegen/box/callableReference/adaptedReferences/inlineVarargInts.kt

@@ -0,0 +1,13 @@
+// !LANGUAGE: +NewInference
+// IGNORE_BACKEND_FIR: JVM_IR
+// WITH_RUNTIME
+// KJS_WITH_FULL_RUNTIME
+
+inline fun foo(x: (Int, Int) -> Int): Int =
+    x(120,3)
+
+fun bar(vararg x: Int): Int =
+    x.sum()
+
+fun box(): String =
+    if (foo(::bar) == 123) "OK" else "FAIL"