Draft: community/gtk4.0: enable tests

Also adds iso-codes and tzdata to dependencies, as some widgets require them. split into separate MR

Failures left to fix:

• Calendar test failures
• Animation test failures? (animation-direction seems to be broken on software rendering/when animations are disabled, so I patched it out)
• Tons of SIGBUSs on armv7/armhf; also consistent with overall buggy behavior on 32-bit arm, see #13604 (closed); will be fixed by !32887 (merged)
• (disabled for now) Notify test failure on x86; seems to be a failure in GtkEntry:progress-pulse-step, could be some weird edge-case there?
• Timeouts on armhf
• In some cases, font weights are appended to their names, which breaks widgetfactory.node tests; has happened at least on ppc64le, aarch64, armv7, armhf and x86
• (ended up just disabling check there) Fix failures on s390x (not sure if it's worth it, nobody uses gtk on these arches anyways)

Wayland

• Failure in gdk/clipboard
• Failure in gdk/seat
• Failure in gtk:reftest / reftest box-shadow-changes-modify-clip.ui on non-x86_64 systems(?)
• Timeout after failed tests