Revert of GN: Normalize the build directory path (patchset #1 id:1 of https://codereview.chromium.org/1708513002/ )

Reason for revert:
Doesn't work on bots (link in previous comment).

Original issue's description:
> GN: Normalize the build directory path
>
> BUG=586906
> TEST=ln -s /tmp out_tmp && out/gn/gn gen out_tmp/Release
>
> Committed: https://crrev.com/89d33db3bfd53fbb3d85bb218ad4db8489a4dc34
> Cr-Commit-Position: refs/heads/master@{#375970}

TBR=hashimoto@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=586906

Review URL: https://codereview.chromium.org/1705313002

Cr-Original-Commit-Position: refs/heads/master@{#376004}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9a3e795d6956aca4656c3c0d7d42541051b0c7c2