Make MPI restart test more robust

Sometimes the shared filesystem is slow and the folder is properly not
synced across MPI processes. This commit adds an extra check to ensure
that all the MPI processes see the tmpfolder before moving forward.

test/restart.jl

@@ -8,6 +8,7 @@ import ClimaCore.DataLayouts: AbstractData
 import ClimaCore.Geometry: AxisTensor
 import ClimaCore.Spaces: AbstractSpace
 import ClimaComms
+import ClimaUtilities.OutputPathGenerator: maybe_wait_filesystem
 pkgversion(ClimaComms) >= v"0.6" && ClimaComms.@import_required_backends
 import Logging
 import NCDatasets
@@ -379,6 +380,10 @@ if MANYTESTS
                             ClimaComms.iamroot(comms_ctx) ? mktempdir(pwd()) :
                             ""
                         output_loc = ClimaComms.bcast(comms_ctx, output_loc)
+                        # Sometimes the shared filesystem doesn't work properly
+                        # and the folder is not synced across MPI processes.
+                        # Let's add an additional check here.
+                        maybe_wait_filesystem(comms_ctx, output_loc)
 
                         job_id = "$(configuration)_$(moisture)_$(precip)_$(topography)_$(radiation)_$(turbconv_mode)"
                         test_dict = Dict(