[ios] Explicitly specify ios_code_signing_identity_description for bots

Recent changes to this value demonstrated the value of having all
the bots provide an explicit value (avoid breaking them when the
default is changed).

Bug: 1086389
Change-Id: I89902abe5d0e2b69931ce7396efca0c8fc884265
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2214549Reviewed-by: Ben Pastene <bpastene@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772214}

tools/mb/mb_config.pyl

@@ -1909,11 +1909,11 @@
     ],
 
     'ios_device_release_compile_only': [
-        'compile_only', 'ios_device',  'ios_disable_code_signing', 'release_bot'
+        'compile_only', 'ios_device', 'ios_google_cert', 'ios_disable_code_signing', 'release_bot'
     ],
 
     'ios_device_release_rbe_compile_only': [
-        'compile_only', 'ios_device',  'ios_disable_code_signing', 'ios_use_goma_rbe', 'release_bot'
+        'compile_only', 'ios_device', 'ios_google_cert', 'ios_disable_code_signing', 'ios_use_goma_rbe', 'release_bot'
     ],
 
     # doesn't have symbol_level=0
@@ -2599,8 +2599,11 @@
       'gn_args': 'target_os="ios"',
     },
 
+    'ios_google_cert': {
+      'gn_args': 'ios_code_signing_identity_description=\"Apple Development\"',
+    },
+
     'ios_chromium_cert': {
-      # defaults to "Apple Development" under ios_sdk.gni
       'gn_args': 'ios_code_signing_identity_description=\"iPhone Developer\"',
     },