Revert changes to swap_refcnt test. (#3721)

* Revert "Fix swap_refcnt.swift, again..."

This reverts commit 2b3c705.

This breaks the build. Please use swift-ci.

* Revert "SILOptimizer: Fix a broken test"

This reverts commit bb9c44f.

This breaks the build. Please use swift-ci.

Author: atrick

test/SILOptimizer/swap_refcnt.swift

@@ -1,25 +1,12 @@
 // RUN: %target-swift-frontend -O -emit-sil %s | FileCheck %s
+// REQUIRES: rdar:27506150> SILOptimizer/swap_refcnt.swift failes after noreturn -> Never changes
 
 // Make sure we can swap two values in an array without retaining anything.
 
-// FIXME: In optimized builds, we inline some stuff, and end up with
-// the following instruction sequence -- %130 is a never-returning
-// function:
-//
-// strong_retain %23 : $Builtin.NativeObject
-// strong_retain %23 : $Builtin.NativeObject
-// strong_retain %23 : $Builtin.NativeObject
-// %130 = apply %121(%125, %114, %118, %120, %126)
-//
-// But really the strong_retains here should be optimized away.
-
-// XFAIL: optimized_stdlib
-
-
 // CHECK-LABEL: sil @_TF11swap_refcnt11swapByIndex
 // CHECK-NOT: strong_retain
 // CHECK-NOT: strong_release
-// CHECK: return %
+// CHECK: return
 public func swapByIndex(A: inout [Int8], x : Int, y : Int) {
   swap(&A[x],&A[y])
 }