[Tests] Add box tests for #KT-59904

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

@@ -0,0 +1,18 @@
+// IGNORE_BACKEND_K1: ANY
+
+lateinit var result: String
+
+fun foo(x: Int, y: Any): Int {
+    result = "OK"
+    return x
+}
+fun foo(x: Any, y: Int): Int {
+    result = "FAIL"
+    return y
+}
+
+fun box(): String {
+    val fooRef: (Int, Any) -> Unit = ::foo
+    fooRef(1, "")
+    return result
+}

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

@@ -0,0 +1,19 @@
+// IGNORE_BACKEND_K1: ANY
+
+fun foo(vararg ii: Int) = 1
+fun foo(vararg ss: String) = 2
+fun foo(i: Int) = 3
+
+val fn1: (Int) -> Int = ::foo
+val fn2: (IntArray) -> Int = ::foo
+val fn3: (Int, Int) -> Int = ::foo // K1 reports NONE_APPLICABLE
+val fn4: (Array<String>) -> Int = ::foo
+
+fun box(): String {
+    if (fn1(1) != 3) return "FAIL 1"
+    if (fn2(intArrayOf(1)) != 1) return "FAIL 2"
+    if (fn3(1, 2) != 1) return "FAIL 3"
+    if (fn4(arrayOf("")) != 2) return "FAIL 4"
+
+    return "OK"
+}