[codesearch] Add phase to builders in 'chromium.infra.codesearch'

tools/mb/mb_config.pyl

Index: tools/mb/mb_config.pyl
diff --git a/tools/mb/mb_config.pyl b/tools/mb/mb_config.pyl
index eaf175f6f90ca242f4354974e771b5adf6131232..a238c14babcd1ba94268967a494daddcb0b914c4 100644
--- a/tools/mb/mb_config.pyl
+++ b/tools/mb/mb_config.pyl
@@ -257,9 +257,16 @@
     },
 
     'chromium.infra.codesearch': {
-      'codesearch-gen-chromium-android': 'codesearch_gen_chromium_android_bot',
-      'codesearch-gen-chromium-chromiumos': 'codesearch_gen_chromium_chromiumos_bot',
-      'codesearch-gen-chromium-linux': 'codesearch_gen_chromium_linux_bot',
+      'codesearch-gen-chromium-android': {
+        'android': 'codesearch_gen_chromium_android_bot',
+      },
+      'codesearch-gen-chromium-chromiumos': {
+        'chromeos': 'codesearch_gen_chromium_chromiumos_bot',
+        'linux': 'codesearch_gen_chromium_linux_bot',
+      },
+      'codesearch-gen-chromium-linux': {
+        'linux': 'codesearch_gen_chromium_linux_bot',
+      },
     },
 
     'chromium.linux': {