elements.cc invokes ApplyAttributesToDictionary using NumberDictionary as its template
parameter. But the declaration of the template method is in js-object.cc, so nobody
can actually compile the version for number dictionary. This is fixed requesting
explicit instantiation for NumberDictionary.

This was breaking GCC build.

Bug: chromium:819294
Change-Id: I685ddc5b97e129d1a534dbdb04025c0932bc5ecd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1649565Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: José Dapena Paz <jose.dapena@lge.com>
Cr-Commit-Position: refs/heads/master@{#62097}