[GN]: Fix bug where cflag vars were not being written on non-PCH builds

On non-PCH builds, the cflags* vars were not being properly written in
the binary output.

Also removed some dead vars.

BUG=535040

Review URL: https://codereview.chromium.org/1359243002

Cr-Original-Commit-Position: refs/heads/master@{#350294}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 4f28b8c3f0895976d060159edd5271c8a6a2a92a
3 files changed
tree: 23567f385f44b02e35f2ea125cbc031b3070eb41
  1. tools/