third_party: symlink //third_party/v8/build => //build

third_party @ 63d81416

-Subproject commit 7f6923ab6e7125238a69d4c0dd8b31f12cb78ce7
+Subproject commit 63d8141691c6e6f0e5b731f8d79f744a00378bf2

tools/third_party.py

@@ -104,6 +104,7 @@ def fix_symlinks():
     remove_and_symlink("v8/third_party/jinja2", tp("jinja2"), True)
     remove_and_symlink("v8/third_party/llvm-build", tp("llvm-build"), True)
     remove_and_symlink("v8/third_party/markupsafe", tp("markupsafe"), True)
+    remove_and_symlink("../../build", tp("v8/build"), True)
 
     # On Windows, git doesn't create the right type of symlink if the symlink
     # and it's target are in different repos. Here we fix the symlinks that