JVM_IR: Fix Inline CallableReferences with Varargs

- Added tests to demonstrate broken behaviour: the interaction of inline
  functions and callable references with varargs and defaults in various
  combinations.
- Refactored InlineCallableReferencesToLambdaPhase to look like and use
  some of the infrastructure from CallableReferenceLowering.
- Lifted some of this infrastructure out to be broadly reusable.

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

@@ -0,0 +1,12 @@
+// !LANGUAGE: +NewInference
+// WITH_RUNTIME
+// IGNORE_BACKEND: JS, JS_IR
+
+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"