cronbuild and tests sometimes fail with ubuntu apt update hash mismatch

Latest cronbuild faild:

https://github.com/DynamoRIO/dynamorio/actions/runs/4089547178/jobs/7052316065
```
Hit:1 http://azure.archive.ubuntu.com/ubuntu focal InRelease
Get:2 http://azure.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:3 https://packages.microsoft.com/ubuntu/20.04/prod focal InRelease [3065 B]
Get:4 http://azure.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Get:5 http://azure.archive.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Hit:6 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu focal InRelease
Get:7 https://packages.microsoft.com/ubuntu/20.04/prod focal/main arm64 Packages [31.5 kB]
Get:8 https://packages.microsoft.com/ubuntu/20.04/prod focal/main amd64 Packages [[17](https://github.com/DynamoRIO/dynamorio/actions/runs/4089547178/jobs/7052316065#step:4:18)1 kB]
Err:8 https://packages.microsoft.com/ubuntu/20.04/prod focal/main amd64 Packages
Hash Sum mismatch
Hashes of expected file:
- Filesize:170735 [weak]
- SHA512:1edb7c982562f2dbeca0dd8ed43606d5dd0382ff412f8543fed6b72656f19f036069df9e539939eeadf0eaad701feb82dd80f32748433ee492b9629e97f831a8
- SHA256:419e404cb66105f40c403169c3f790d75dd49fd186234ff60bd54f8b76b55997
Hashes of received file:
- SHA512:b7978b5542d5dbd545962909385287dc220e40b2b44e25607282e2aec64c17515443b717d2df607e83b8b19736110dbaafd9d6e71f92ac72f56beb7830875777
- SHA256:550bc6b431fbd559e4fef4c176d0301b63d3487efaf1ca1d18d0749f1bbce7a4
- Filesize:170735 [weak]
Last modification reported: Sat, 04 Feb 2023 02:21:05 +0000
Release file created at: Sat, 04 Feb 2023 02:24:54 +0000
Get:9 https://packages.microsoft.com/ubuntu/20.04/prod focal/main all Packages [2176 B]
Get:10 https://packages.microsoft.com/ubuntu/20.04/prod focal/main armhf Packages [12.3 kB]
Err:10 https://packages.microsoft.com/ubuntu/20.04/prod focal/main armhf Packages

Get:11 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [2345 kB]
Get:12 http://azure.archive.ubuntu.com/ubuntu focal-updates/main Translation-en [405 kB]
Get:13 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 c-n-f Metadata [16.3 kB]
Get:14 http://azure.archive.ubuntu.com/ubuntu focal-updates/universe amd64 Packages [1022 kB]
Get:15 http://azure.archive.ubuntu.com/ubuntu focal-updates/universe Translation-en [237 kB]
Get:16 http://azure.archive.ubuntu.com/ubuntu focal-updates/universe amd64 c-n-f Metadata [23.5 kB]
Get:17 http://azure.archive.ubuntu.com/ubuntu focal-backports/universe amd64 Packages [24.9 kB]
Get:[18](https://github.com/DynamoRIO/dynamorio/actions/runs/4089547178/jobs/7052316065#step:4:19) http://azure.archive.ubuntu.com/ubuntu focal-backports/universe amd64 c-n-f Metadata [880 B]
Get:19 http://azure.archive.ubuntu.com/ubuntu focal-security/main amd64 Packages [1968 kB]
Get:20 http://azure.archive.ubuntu.com/ubuntu focal-security/main Translation-en [322 kB]
Get:21 http://azure.archive.ubuntu.com/ubuntu focal-security/main amd64 c-n-f Metadata [12.0 kB]
Get:22 http://azure.archive.ubuntu.com/ubuntu focal-security/universe amd64 Packages [792 kB]
Get:23 http://azure.archive.ubuntu.com/ubuntu focal-security/universe Translation-en [154 kB]
Get:24 http://azure.archive.ubuntu.com/ubuntu focal-security/universe amd64 c-n-f Metadata [17.0 kB]
Fetched 7895 kB in 2s (4566 kB/s)
Reading package lists...
E: Failed to fetch https://packages.microsoft.com/ubuntu/20.04/prod/dists/focal/main/binary-amd64/Packages.gz Hash Sum mismatch
Hashes of expected file:
- Filesize:170735 [weak]
- SHA512:1edb7c982562f2dbeca0dd8ed43606d5dd0382ff412f8543fed6b72656f[19](https://github.com/DynamoRIO/dynamorio/actions/runs/4089547178/jobs/7052316065#step:4:20)f036069df9e539939eeadf0eaad701feb82dd80f32748433ee492b9629e97f831a8
- SHA256:419e404cb66105f40c403169c3f790d75dd49fd186234ff60bd54f8b76b55997
Hashes of received file:
- SHA512:b7978b5542d5dbd545962909385287dc2[20](https://github.com/DynamoRIO/dynamorio/actions/runs/4089547178/jobs/7052316065#step:4:21)e40b2b44e25607282e2aec64c17515443b717d2df607e83b8b19736110dbaafd9d6e71f92ac72f56beb7830875777
- SHA256:550bc6b431fbd559e4fef4c176d0301b63d3487efaf1ca1d18d0749f1bbce7a4
- Filesize:170735 [weak]
Last modification reported: Sat, 04 Feb 2023 02:[21](https://github.com/DynamoRIO/dynamorio/actions/runs/4089547178/jobs/7052316065#step:4:22):05 +0000
Release file created at: Sat, 04 Feb 2023 02:24:54 +0000
E: Failed to fetch https://packages.microsoft.com/ubuntu/20.04/prod/dists/focal/main/binary-armhf/Packages.gz
E: Some index files failed to download. They have been ignored, or old ones used instead.
Error: Process completed with exit code 100.
```

Start with the linked GitHub Actions run and inspect the cronbuild and test setup that runs apt update against packages.microsoft.com on Ubuntu 20.04. Determine why the package indexes produce hash mismatches and identify a reliable resolution; done means the affected cronbuild and tests complete without this apt failure.

Written by the indexing model from the issue text.