[infra] Add stress_snapshot variant to fyi bots

These are currently expected to fail quite often since support is
still incomplete. Let's add them to fyi bots for now and extend
coverage later.

Bug: v8:10416,chromium:1043058
Change-Id: I1fe60c85f3fcf1e7e2981c28908208b348150b7f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2181286
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67587}

infra/testing/builders.pyl

@@ -310,12 +310,13 @@
       'os': 'Ubuntu-16.04',
     },
     'tests': [
+      # Infra staging.
+      {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 2},
       # Stress sampling.
       {'name': 'mjsunit', 'variant': 'stress_sampling'},
       {'name': 'webkit', 'variant': 'stress_sampling'},
-      # Infra staging.
-      {'name': 'test262', 'variant': 'infra_staging', 'shards': 2},
-      {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 2},
+      # Stress snapshot.
+      {'name': 'mjsunit', 'variant': 'stress_snapshot'},
     ],
   },
   'v8_linux64_msan_rel': {
@@ -960,8 +961,10 @@
       # Infra staging.
       {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 2},
       # Stress sampling.
-      {'name': 'mjsunit', 'variant': 'stress_sampling', 'shards': 1},
-      {'name': 'webkit', 'variant': 'stress_sampling', 'shards': 1},
+      {'name': 'mjsunit', 'variant': 'stress_sampling'},
+      {'name': 'webkit', 'variant': 'stress_sampling'},
+      # Stress snapshot.
+      {'name': 'mjsunit', 'variant': 'stress_snapshot'},
     ],
   },
   'V8 Linux64 - debug - perfetto': {
@@ -983,10 +986,12 @@
     },
     'tests': [
       # Infra staging.
-      {'name': 'v8testing', 'variant': 'infra_staging', 'shards': 1},
+      {'name': 'v8testing', 'variant': 'infra_staging'},
       # Stress sampling.
-      {'name': 'mjsunit', 'variant': 'stress_sampling', 'shards': 1},
-      {'name': 'webkit', 'variant': 'stress_sampling', 'shards': 1},
+      {'name': 'mjsunit', 'variant': 'stress_sampling'},
+      {'name': 'webkit', 'variant': 'stress_sampling'},
+      # Stress snapshot.
+      {'name': 'mjsunit', 'variant': 'stress_snapshot'},
     ],
   },
   'V8 Linux64 - gcov coverage': {