Promote aarch64 Ubuntu test_xpickle to stable (#665)

Author: StanFromIreland

master/custom/builders.py

@@ -94,6 +94,9 @@
     ("AMD64 Windows11 Refleaks", "ware-win11", Windows64RefleakBuild),
     ("AMD64 Windows Server 2022 NoGIL", "itamaro-win64-srv-22-aws", Windows64NoGilBuild),
     ("AMD64 Windows PGO NoGIL", "itamaro-win64-srv-22-aws", Windows64PGONoGilBuild),
+
+    # Tests that require the 'tzdata' and 'xpickle' resources
+    ("aarch64 Ubuntu Oddballs", "stan-aarch64-ubuntu", UnixOddballsBuild),
 ]
 
 
@@ -207,13 +210,9 @@
 
 # -- Unstable Tier-1 builders -------------------------------------------
 UNSTABLE_BUILDERS_TIER_1 = [
-
     # Ubuntu Linux AArch64
     ("aarch64 Ubuntu 24.04 BigMem", "diegorusso-aarch64-bigmem", UnixBigmemBuild),
 
-    # Tests that require the 'tzdata' and 'xpickle' resources
-    ("aarch64 Ubuntu Oddballs", "stan-aarch64-ubuntu", UnixOddballsBuild),
-
     # Linux x86-64 GCC
     # Fedora Rawhide is unstable
     ("AMD64 Fedora Rawhide", "cstratak-fedora-rawhide-x86_64", FedoraRawhideBuild),