[test] Add "trusted" testing variant to a subset of bots

Bug: chromium:798982
Change-Id: I096e2df5a5f8d038c980bc9f575857256f0a01df
Reviewed-on: https://chromium-review.googlesource.com/852073Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50378}

tools/testrunner/local/variants.py

@@ -18,6 +18,7 @@ ALL_VARIANT_FLAGS = {
   # https://chromium-review.googlesource.com/c/452620/ for more discussion.
   "nooptimization": [["--noopt"]],
   "stress_background_compile": [["--background-compile", "--stress-background-compile"]],
+  "trusted": [["--no-untrusted-code-mitigations"]],
   "wasm_traps": [["--wasm_trap_handler", "--invoke-weak-callbacks", "--wasm-jit-to-native"]],
 
   # Alias of exhaustive variants, but triggering new test framework features.

tools/testrunner/standard_runner.py

@@ -49,7 +49,7 @@ VARIANT_ALIASES = {
   # Shortcut for the two above ("more" first - it has the longer running tests).
   "exhaustive": MORE_VARIANTS + VARIANTS,
   # Additional variants, run on a subset of bots.
-  "extra": ["future", "liftoff"],
+  "extra": ["future", "liftoff", "trusted"],
 }
 
 GC_STRESS_FLAGS = ["--gc-interval=500", "--stress-compaction",