Revert of Un-nest configs in GN files. (patchset #3 id:40001 of )

Reason for revert:
This breaks why these configs exist in the first place and seriously breaks the clang/win gn build (which is what these configs exist for).

Original issue's description:
> Un-nest configs in GN files.
> People sometimes nest targets or configs, usually with the assumption that this limits the visibility of a config to within a target. But this nesting provides no visibility restrictions over declaring it outside of a block.
> Un-nest for clarity.
> Committed:
> Cr-Commit-Position: refs/heads/master@{#346461},

Review URL:

Cr-Original-Commit-Position: refs/heads/master@{#346695}
Cr-Mirrored-Commit: 0cb5abbf230f3c30e3499d4e787f059ed723dd3c
1 file changed