The source set only contained a header file, which caused problems
when compiling a static library with VS.

R=machenbach@chromium.org
BUG=v8:6158

Change-Id: I3eed4a888e72cf6a2917190e4a1db7b38006cd0c
Reviewed-on: https://chromium-review.googlesource.com/463027Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#44263}