Support boxing/unboxing for captured vars of inline class types

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

@@ -0,0 +1,71 @@
+// !LANGUAGE: +InlineClasses
+
+inline class UInt(private val value: Int) {
+    operator fun plus(other: UInt): UInt = UInt(value + other.asValue())
+
+    fun asValue(): Int = value
+}
+
+val Int.u get() = UInt(this)
+
+var global = 0.u
+
+fun testInlined(x: UInt?, withAssert: Boolean) {
+    x?.myLet {
+        takeUInt(it)
+        takeUInt(x)
+    }
+
+    x?.myLet {
+        takeNullableUInt(it)
+        takeNullableUInt(x)
+    }
+
+    if (withAssert) {
+        x!!.myLet {
+            takeUInt(it)
+            takeUInt(x)
+        }
+    }
+}
+
+fun testNotInlined(x: UInt?) {
+    x?.myLet {
+        takeUInt(it)
+        takeUInt(x)
+    }
+
+    x?.myLet {
+        takeNullableUInt(it)
+        takeNullableUInt(x)
+    }
+}
+
+fun takeUInt(y: UInt) {
+    global += y
+}
+
+fun takeNullableUInt(y: UInt?) {
+    if (y != null) {
+        global += y
+    }
+}
+
+inline fun <T> T.myLet(f: (T) -> Unit) = f(this)
+fun <T> T.nonInlineLet(f: (T) -> Unit) = f(this)
+
+fun box(): String {
+    val u = 1.u
+    testInlined(u, true)
+    if (global.asValue() != 6) return "fail 1"
+
+    global = 0.u
+    testInlined(null, false)
+    if (global.asValue() != 0) return "fail 2"
+
+    global = 0.u
+    testNotInlined(u)
+    if (global.asValue() != 4) return "fail 3"
+
+    return "OK"
+}

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

@@ -0,0 +1,31 @@
+// !LANGUAGE: +InlineClasses
+
+inline class UInt(val value: Int)
+
+fun test(x: UInt?) {
+    x?.myLet { // unbox
+        takeUInt(it)
+        takeUInt(x) // unbox
+    }
+
+    x?.myLet { // unbox
+        takeNullableUInt(it) // box
+        takeNullableUInt(x)
+    }
+
+    x!!.myLet { // unbox
+        takeUInt(it)
+        takeUInt(x) // unbox
+    }
+}
+
+fun takeUInt(y: UInt) {}
+fun takeNullableUInt(y: UInt?) {}
+
+inline fun <T> T.myLet(f: (T) -> Unit) = f(this)
+
+// 1 INVOKESTATIC UInt\$Erased.box
+// 5 INVOKEVIRTUAL UInt.unbox
+
+// 0 intValue
+// 0 valueOf