[infra] Add Maglev test variant to GC stress builders

Bug: v8:13116
Cq-Include-Trybots: luci.v8.try.triggered:v8_linux64_gc_stress_dbg_ng_triggered
Change-Id: I0041fd3820d464e142269c99cdf2d24ea890b286
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3812041Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Almothana Athamneh <almuthanna@chromium.org>
Auto-Submit: Almothana Athamneh <almuthanna@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82225}

infra/testing/builders.pyl

@@ -427,8 +427,19 @@
       'os': 'Ubuntu-18.04',
     },
     'tests': [
-      {'name': 'mjsunit', 'variant': 'slow_path', 'test_args': ['--gc-stress'], 'shards': 2},
       {'name': 'd8testing', 'test_args': ['--gc-stress'], 'shards': 5},
+      {
+        'name': 'mjsunit',
+        'variant': 'slow_path',
+        'test_args': ['--gc-stress'],
+        'shards': 2
+      },
+      {
+        'name': 'mjsunit',
+        'variant': 'maglev',
+        'test_args': ['--gc-stress'],
+        'shards': 2
+      },
     ],
   },
   'v8_linux64_gcc_rel_ng_triggered': {
@@ -1394,6 +1405,12 @@
         'test_args': ['--gc-stress'],
         'shards': 2,
       },
+      {
+        'name': 'mjsunit',
+        'variant': 'maglev',
+        'test_args': ['--gc-stress'],
+        'shards': 2
+      },
     ],
   },
   'V8 Linux64 - gcov coverage': {