Without this, the files are ignored when V8 source is copied to another
repository (for example Node.js).

Change-Id: Ia1ac2d2673d13a266f2beaa1dadd93df903afd5d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2972915Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michaël Zasso <mic.besace@gmail.com>
Cr-Commit-Position: refs/heads/master@{#75276}