Fix tools_unittests in GN.
Fix tools_unittests in GN.

tools_unittests were failing when generated by GN and running on a device.

BUG=webrtc:5949
NOTRY=True

Review-Url: https://codereview.webrtc.org/2233843002
Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#13714}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 4556b450765116072f9700e0619c86b0f9b06588

Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk