Fix the GN upload (build) flags to not depend on GN.

Fix the GN upload (build) flags to not depend on GN.

This changes the GN args we use on the linux_chromium_gn_upload
bot to not require a runtime dependency on GN.

This CL also deletes the old ntries for the 32-bit and 64-bit
upload bots (we just do 64-bit now, using the newer builder named
linux_chromium_gn_upload).

TBR=brettw@chromium.org
BUG=

Committed: https://crrev.com/5a47c761a09130cd75332b443c92f7e312070b26
Cr-Commit-Position: refs/heads/master@{#333140}

[Dirk Pranke, 2015-06-05 20:22:15]

The CQ bit was checked by dpranke@chromium.org

[commit-bot: I haz the power, 2015-06-05 20:24:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1168743003/1

[brettw, 2015-06-05 20:30:02]

lgtm

[commit-bot: I haz the power, 2015-06-05 21:39:54]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-05 21:40:51]

Patchset 1 (id:??) landed as
https://crrev.com/5a47c761a09130cd75332b443c92f7e312070b26
Cr-Commit-Position: refs/heads/master@{#333140}