Merge bitcoin#21112: ci: use Focal for macOS cross builds

ac24af4 ci: use Ubuntu Focal for macOS cross build (fanquake)

Pull request description:

  I had assumed Cirrus was spinning up Docker containers to run the CI,
  however we are actaully running on the Cirrus machines themselves. See
  `DANGER_RUN_CI_ON_HOST` and in the logs:
  ```bash
  Running on host system without docker wrapper
  ```

  So with this change we will actually be using Focal for the macOS cross build.

  Follow up to bitcoin#21036.

  This originally contained Windows changes, and an attempt to get Cirrus running without `DANGER_RUN_CI_ON_HOST`, however that seems non-trival, so Windows changes have been dropped from here for now.

ACKs for top commit:
  MarcoFalke:
    cr ACK ac24af4

Tree-SHA512: 587ba5acf741bcefecf1bc262fa1177f565ebfa9de56125eca19ed3c7db7b9aabfb96866e9c140681b88cb7015a3ded2bc6b4b1b235543d6f6e9dfc6984d569f

Author: MarcoFalke

.cirrus.yml

@@ -149,7 +149,7 @@ task:
     FILE_ENV: "./ci/test/00_setup_env_native_nowallet.sh"
 
 task:
-  name: 'macOS 10.12 [gui, no tests] [bionic]'
+  name: 'macOS 10.12 [gui, no tests] [focal]'
   << : *GLOBAL_TASK_TEMPLATE
   container:
     image: ubuntu:focal

ci/test/00_setup_env_mac.sh

@@ -8,7 +8,7 @@ export LC_ALL=C.UTF-8
 
 export CONTAINER_NAME=ci_macos_cross
 export HOST=x86_64-apple-darwin
-export PACKAGES="cmake libcap-dev libz-dev libbz2-dev python3-setuptools"
+export PACKAGES="cmake libcap-dev libz-dev libbz2-dev libtinfo5 python3-setuptools"
 export XCODE_VERSION=12.2
 export XCODE_BUILD_ID=12B45b
 export RUN_UNIT_TESTS=false