Do not use internal source in H.264 bitstream rewriting tests.
Do not use internal source in H.264 bitstream rewriting tests.

Bug: None
Change-Id: Ice1ffb4371ade57bd642f5fe86d6432f2c175d71
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/179281
Reviewed-by: Niels Moller <0057859e47d61d90529d0f66d9ef692cefedb46a@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <76788ac3efd229e9d156135d9ceb7fef65c45da4@webrtc.org>
Commit-Queue: Mirta Dvornicic <c6f473f74a061e7a4ef17c2c04eac029911f2b6c@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#31730}

ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc