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.

Review URL: https://codereview.chromium.org/1318823008

Cr-Commit-Position: refs/heads/master@{#346461}
18 files changed