Gradually migrate tests from 'Linux Tests' to run on bionic bots

This is the last step to migrate the below tests to bionic bots:
- interactive_ui_tests (green in [1])
- not_site_per_process_blink_web_tests (green in [1])
- browser_tests (disabled failed tests)
- blink_web_tests (disabled failed tests)

As linux-rel mirrors 'Linux Tests', this change directs 31% tests
from linux-rel to bionic test bots.

[1] https://ci.chromium.org/p/chromium/builders/ci/linux-bionic-rel

BUG=1199425
TEST=./generate_buildbot_json_unittest.py

Change-Id: I1be73fbedcb269bd031417476a9cdeba22074a4f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2874960
Reviewed-by: Ben Pastene <bpastene@chromium.org>
Reviewed-by: Gary Tong <gatong@chromium.org>
Commit-Queue: Xinan Lin <linxinan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#879595}
NOKEYCHECK=True
GitOrigin-RevId: 841049a20c173362a3c25442d24289584496e940
2 files changed