Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/boxingOptimization/unsafeRemoving.kt

@@ -0,0 +1,35 @@
+// WITH_RUNTIME
+
+import kotlin.test.assertEquals
+
+fun returningBoxed() : Int? = 1
+fun acceptingBoxed(x : Int?) : Int ? = x
+
+class A(var x : Int? = null)
+
+fun box() : String {
+    assertEquals(1, returningBoxed())
+    assertEquals(1, acceptingBoxed(1))
+
+    val a = A()
+    a.x = 1
+    assertEquals(1, a.x)
+
+    val b = Array<Int?>(1, { null })
+    b[0] = 1
+    assertEquals(1, b[0])
+
+    val x: Int? = 1
+    assertEquals(1, x!!.hashCode())
+
+    val y: Int? = 1000
+    val z: Int? = 1000
+    val res = y === z
+
+    val c1: Any = if (1 == 1) 0 else "abc"
+    val c2: Any = if (1 != 1) 0 else "abc"
+    assertEquals(0, c1)
+    assertEquals("abc", c2)
+
+    return "OK"
+}