Explicitly say "_compile_" for ARM and Clang and GCC. Explicitly say "_arm_" for mobiles. Explicitly say "_x86_" for Windows. Fill in some gaps where both tester and compile-only bots are viable. Also remove unused "experimental" tryjobs. No-Try: True Bug: webrtc:10072 Change-Id: Ib22e0518fc1e600b237c3c687994f27c7e88b8b3 Reviewed-on: https://webrtc-review.googlesource.com/c/112585 Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org> Commit-Queue: Oleh Prypin <oprypin@webrtc.org> Cr-Commit-Position: refs/heads/master@{#25872}