Add some tests on adapted references with varargs and reflection

Also rename "varargAndDefaults" test directory to "adaptedReferences"

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

@@ -0,0 +1,28 @@
+// !LANGUAGE: +NewInference +FunctionReferenceWithDefaultValueAsOtherType
+// IGNORE_BACKEND_FIR: JVM_IR
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+object E : Exception()
+
+fun foo(
+        a: String = "fail",
+        b: Int,
+        c: Double = 3.14,
+        vararg d: String,
+        e: Throwable = E
+) {
+    assertEquals("ok", a)
+    assertEquals(42, b)
+    assertEquals(3.14, c)
+    assertEquals(0, d.size)
+    assertEquals(E, e)
+}
+
+fun bar(f: (String, Int) -> Unit) = f("ok", 42)
+
+fun box(): String {
+    bar(::foo)
+    return "OK"
+}