test: do jit.flush() after jit.off() on arm64

JIT has been disabled for these 3 tests on arm64 to avoid weird fails, but
they are still flaky in CI. Perhaps the JIT traces from other tests affect
them. Let's try to do jit.flush() together with jit.off().

Also disable JIT for pagination_netbox_test.lua, which suffers from the
same problem as pagination_test.lua.

Part of #6599
Part of #7739
Part of #8011

NO_DOC=testing stuff
NO_CHANGELOG=testing stuff