tests: enable SILOptimizer/copy-to-borrow-optimization.sil for all OSes

By defining its own array structs, which are independent from objc interop.
Also, the requires-line was wrong anyway. The test didn't run on macos either.

Author: eeckstein

test/SILOptimizer/copy-to-borrow-optimization.sil

@@ -1,5 +1,4 @@
 // RUN: %target-sil-opt -copy-to-borrow-optimization %s | %FileCheck %s
-// REQUIRES: macosx
 
 sil_stage canonical
 
@@ -82,6 +81,22 @@ struct NonTrivialStruct {
   var val: Klass
 }
 
+class MyArrayStorageBase {
+  @_hasStorage let countAndCapacity: Int
+}
+
+struct MyBridgeStorage {
+  let rawValue: Builtin.NativeObject
+}
+
+struct MyArrayBuffer {
+  let storage: MyBridgeStorage
+}
+
+struct MyArray {
+  let buffer: MyArrayBuffer
+}
+
 sil @getKlass : $@convention(thin) () -> @owned Klass
 sil @guaranteed_klass_user : $@convention(thin) (@guaranteed Klass) -> ()
 sil @use_inguaranteed : $@convention(thin) (@in_guaranteed Klass) -> ()
@@ -2242,19 +2257,19 @@ bb1(%1 : @guaranteed $C):
 // CHECK-LABEL: sil [ossa] @borrowed_from_forward2 : {{.*}} {
 // CHECK-NOT:   copy_value
 // CHECK-LABEL: } // end sil function 'borrowed_from_forward2'
-sil [ossa] @borrowed_from_forward2 : $@convention(thin) (@guaranteed Array<Int>) -> () {
-bb0(%0 : @guaranteed $Array<Int>):
-  %1 = struct_extract %0, #Array._buffer
-  %2 = struct_extract %1, #_ArrayBuffer._storage
-  %3 = struct_extract %2, #_BridgeStorage.rawValue
-  %4 = unchecked_ref_cast %3 to $__ContiguousArrayStorageBase
+sil [ossa] @borrowed_from_forward2 : $@convention(thin) (@guaranteed MyArray) -> () {
+bb0(%0 : @guaranteed $MyArray):
+  %1 = struct_extract %0, #MyArray.buffer
+  %2 = struct_extract %1, #MyArrayBuffer.storage
+  %3 = struct_extract %2, #MyBridgeStorage.rawValue
+  %4 = unchecked_ref_cast %3 to $MyArrayStorageBase
   br bb1(%4)
 
-bb1(%6 : @guaranteed $__ContiguousArrayStorageBase):
+bb1(%6 : @guaranteed $MyArrayStorageBase):
   %7 = borrowed %6 from (%0)
   %8 = copy_value %7
   %9 = begin_borrow %8
-  %10 = ref_element_addr [immutable] %9, #__ContiguousArrayStorageBase.countAndCapacity
+  %10 = ref_element_addr [immutable] %9, #MyArrayStorageBase.countAndCapacity
   end_borrow %9
   destroy_value %8
   %13 = tuple ()