Support passing inline class values with spread operator

compiler/testData/codegen/box/inlineClasses/passInlineClassWithSpreadOperatorToVarargs.kt

@@ -0,0 +1,17 @@
+// !LANGUAGE: +InlineClasses
+
+inline class UInt(val value: Int)
+
+fun <T> last(vararg e: T): T = e[e.size - 1]
+fun <T> first(vararg e: T): T = e[0]
+
+fun box(): String {
+    val u0 = UInt(0)
+    val us = arrayOf(UInt(1), UInt(2), UInt(3))
+
+    if (last(u0, *us).value != 3) return "fail"
+    if (first(*us, u0).value != 1) return "fail"
+    if (first(u0, *us).value != 0) return "fail"
+
+    return "OK"
+}

compiler/testData/codegen/bytecodeText/inlineClasses/passInlineClassesWithSpreadOperatorToVarargs.kt

@@ -0,0 +1,20 @@
+// !LANGUAGE: +InlineClasses
+
+inline class UInt(val u: Int)
+
+fun <T> takeVarargs(vararg e: T) {}
+
+fun test(u1: UInt, u2: UInt, us: Array<UInt>) {
+    takeVarargs(*us) // copy + checkcast
+    takeVarargs(u1, u2, *us) // 2 box + ...
+}
+
+// 2 INVOKESTATIC UInt\$Erased.box
+// 0 INVOKEVIRTUAL UInt.unbox
+
+// 2 CHECKCAST \[LUInt
+
+// 0 CHECKCAST \[Ljava/lang/Integer
+
+// 0 intValue
+// 0 valueOf