[NFC] Handle Windows error spelling difference

lolsob

Author: beccadax

test/Sema/access-notes-invalid.swift

@@ -1,5 +1,5 @@
 // RUN: %target-swift-frontend -typecheck -primary-file %/s -access-notes-path %/S/Inputs/missing.accessnotes 2>&1 | %FileCheck --check-prefix=CHECK-MISSING %s
-// CHECK-MISSING: <unknown>:0: warning: ignored access notes file at 'SOURCE_DIR/test/Sema/Inputs/missing.accessnotes' because it cannot be read: No such file or directory{{$}}
+// CHECK-MISSING: <unknown>:0: warning: ignored access notes file at 'SOURCE_DIR/test/Sema/Inputs/missing.accessnotes' because it cannot be read: {{[Nn]}}o such file or directory{{$}}
 
 // RUN: %target-typecheck-verify-swift -access-notes-path %S/Inputs/bad.accessnotes -verify-additional-file %S/Inputs/bad.accessnotes