[test] IRGen: Adjust FileCheck pattern where attribute order changed in upstream LLVM

`alias nocapture swiftself` -> `alias swiftself captures(none)`.

`nocapture` became `captures(none)` in
29441e4f5fa5f5c7709f7cf180815ba97f611297 (llvm-project).

This is intended to reduce future conflicts with rebranch.

Author: AnthonyLatsis

test/IRGen/raw_layout.swift

@@ -348,7 +348,7 @@ entry(%K: $*Keymaster):
     return undef : $()
 }
 
-// CHECK: define {{.*}}swiftcc ptr @get_cell_addr(ptr %"Cell<T>", ptr {{.*}} swiftself [[SELF:%.*]])
+// CHECK: define {{.*}}swiftcc ptr @get_cell_addr(ptr %"Cell<T>", ptr {{.*}} swiftself{{.*}} [[SELF:%.*]])
 // CHECK-NEXT:   entry:
 // CHECK-NEXT:     ret ptr [[SELF]]
 sil @get_cell_addr : $@convention(method) <T> (@in_guaranteed Cell<T>) -> UnsafeMutablePointer<T> {