analysis.timing: Add missing @Nullable annotations

analysis.timing: Add missing @Nullable annotations

The updateTableModel() method supports null parameters, we just need
to add missing @Nullable annotations to fix a compilation warning.

Also annotate CompletableFuture.supplyAsync() methods, they return
a new CompletableFuture, so its return can be @NonNull.

Change-Id: Ieef346b03d0e676c19c4f8cea3568870fc852e37
Signed-off-by: Alexandre Montplaisir <alexmonthy@efficios.com>
Reviewed-on: https://git.eclipse.org/r/67187
Reviewed-by: Hudson CI
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>