CI: Bump up ARM timeouts

We used to have a fairly bimodal distribution of successful ARM test
times: roughly 2/3 of the time, tests would take 800-1800s (~15-30min),
and 1/3 of the time they would take more like 2000-5400s (~30-90min).

Starting around August, the bimodal distribution is gone, with only the
longer expected test times remaining. Timeouts have increased, leaving
the ARM jobs frequently failing spuriously. Increase the timeouts to
get better signal from the tests.

Change-Id: I56165dc6d877bd9e56d7160dd28c6c60f339d730

.zuul.yaml

@@ -83,6 +83,7 @@
     description: |
       Run unit tests for an OpenStack Python project under cPython
       version 3.8 on top of arm64 architecture.
+    timeout: 7200
 
 - job:
     name: swift-tox-py39-arm64
@@ -91,6 +92,7 @@
     description: |
       Run unit tests for an OpenStack Python project under cPython
       version 3.9 on top of arm64 architecture.
+    timeout: 7200
 
 - job:
     name: swift-tox-py39
@@ -228,6 +230,7 @@
       Uses tox with the ``func-encryption-py3`` environment.
       It sets TMPDIR to an XFS mount point created via
       tools/test-setup.sh.
+    timeout: 7200
 
 - job:
     name: swift-tox-func-py38-arm64
@@ -240,6 +243,7 @@
       Uses tox with the ``func-py3`` environment.
       It sets TMPDIR to an XFS mount point created via
       tools/test-setup.sh.
+    timeout: 7200
 
 - job:
     name: swift-tox-func-ec-py38