Ferrochrome: Add boot tests

This test requires 12G+ disk space on host, and roughly takes 10m to complete.

Bug: 327313864
Test: Both `atest ferrochrome-tests` and `ferrochrome.sh`
Change-Id: I9f29021e7ecb20a104ec08a3bbf1e0ba41843e87
diff --git a/TEST_MAPPING b/TEST_MAPPING
index db0b43a..b6a6bf3 100644
--- a/TEST_MAPPING
+++ b/TEST_MAPPING
@@ -64,6 +64,9 @@
     {
       "name": "AvfRkpdAppGoogleIntegrationTests",
       "keywords": ["internal"]
+    },
+    {
+      "name": "ferrochrome-tests"
     }
   ],
   "postsubmit": [