[test] Bump shards on slow bots

No-Try: true
Change-Id: Ib665f238db8dba7ca460f1fdb84e0e0e3a3d9e97
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3234720
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#77476}

infra/testing/builders.pyl

@@ -282,7 +282,7 @@
     'tests': [
       {'name': 'mjsunit_sp_frame_access'},
       {'name': 'mozilla'},
-      {'name': 'test262', 'variant': 'default'},
+      {'name': 'test262', 'variant': 'default', 'shards': 2},
       {'name': 'v8testing', 'shards': 7},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 7},
     ],
@@ -1743,7 +1743,7 @@
     'tests': [
       {'name': 'mjsunit_sp_frame_access'},
       {'name': 'mozilla'},
-      {'name': 'test262', 'variant': 'default'},
+      {'name': 'test262', 'variant': 'default', 'shards': 2},
       {'name': 'v8testing', 'shards': 6},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 3},
       # Armv8-a.
@@ -1791,7 +1791,7 @@
     'tests': [
       {'name': 'mjsunit_sp_frame_access', 'shards': 6},
       {'name': 'mozilla', 'shards': 6},
-      {'name': 'test262', 'variant': 'default'},
+      {'name': 'test262', 'variant': 'default', 'shards': 2},
       {'name': 'v8testing', 'shards': 10},
       {'name': 'v8testing', 'variant': 'extra', 'shards': 10},
       # Armv8-a.