Revert of Remove linux_internal from the autoroller CQ. (patchset #1 id:1 of https://codereview.webrtc.org/2985933002/ )

Reason for revert:
linux_internal now checks that the CL is authored by a googler before executing the tests

Original issue's description:
> Remove linux_internal from the autoroller CQ.
>
> The CQ no longer has permission to schedule builds in linux_internal.
>
> NOTRY=True
> TBR=kjellander@webrtc.org
> BUG=None
>
> Review-Url: https://codereview.webrtc.org/2985933002
> Cr-Commit-Position: refs/heads/master@{#19178}
> Committed: 5ba9730265

TBR=mbonadei@webrtc.org,kjellander@webrtc.org,nodir@chromium.org
BUG=None
NOTRY=True

Review-Url: https://codereview.webrtc.org/2990233002
Cr-Commit-Position: refs/heads/master@{#19240}

tools_webrtc/autoroller/roll_deps.py

@@ -27,6 +27,11 @@ DONT_AUTOROLL_THESE = [
   'src/webrtc/examples/androidtests/third_party/gradle',
 ]
 
+# Run these CQ trybots in addition to the default ones in infra/config/cq.cfg.
+EXTRA_TRYBOTS = (
+    'master.internal.tryserver.corp.webrtc:linux_internal'
+)
+
 WEBRTC_URL = 'https://chromium.googlesource.com/external/webrtc'
 CHROMIUM_SRC_URL = 'https://chromium.googlesource.com/chromium/src'
 CHROMIUM_COMMIT_TEMPLATE = CHROMIUM_SRC_URL + '/+/%s'
@@ -316,6 +321,7 @@ def GenerateCommitMessage(current_cr_rev, new_cr_rev, current_commit_pos,
 
   commit_msg.append('TBR=%s' % tbr_authors)
   commit_msg.append('BUG=None')
+  commit_msg.append('CQ_INCLUDE_TRYBOTS=%s' % EXTRA_TRYBOTS)
   return '\n'.join(commit_msg)