UnXFAIL and fix the array_contentof_opt test

<rdar://problem/36587088>

Author: Max Moiseev

test/SILOptimizer/array_contentof_opt.swift

@@ -1,7 +1,5 @@
 // RUN: %target-swift-frontend -O -sil-verify-all -emit-sil  %s | %FileCheck %s
 // REQUIRES: swift_stdlib_no_asserts,optimized_stdlib
-// FIXME: <rdar://problem/36587088>
-// XFAIL: linux
 
 // This is an end-to-end test of the array(contentsOf) -> array(Element) optimization
 
@@ -34,7 +32,7 @@ public func testThreeInts(_ a: inout [Int]) {
 
 // CHECK-LABEL: sil @{{.*}}testTooManyInts
 // CHECK-NOT: apply
-// CHECK:        [[F:%[0-9]+]] = function_ref  @$SSa6append10contentsOfyqd___t7ElementQyd__Rszs8SequenceRd__lFSi_SaySiGTg5Tf4gn_n
+// CHECK:        [[F:%[0-9]+]] = function_ref  @$SSa6append10contentsOfyqd___t7ElementQyd__Rszs8SequenceRd__lFSi_SaySiGTg5
 // CHECK-NOT: apply
 // CHECK:        apply [[F]]
 // CHECK-NOT: apply