cq: explicitly mark presubmit tryjob as not re-usable in CQ.
cq: explicitly mark presubmit tryjob as not re-usable in CQ.

No change in behavior, just making it explicit how CQ is treating
this builder.

No-Try: True
Bug: chromium:893955
Change-Id: Icf363b44a355af9278541a0c0549e530d679e78f
Reviewed-on: https://webrtc-review.googlesource.com/c/105820
Reviewed-by: Patrik Höglund <b486136ee68458b09c92c86c39f451c87d6ef6a1@webrtc.org>
Commit-Queue: Oleh Prypin <5baa3e04f9bd6ba7a2a4b56625a3c84f19237cdb@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#25157}
TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc