Amr: Add printing of simulation time (#3392)

A very small PR to add the printing of simulation time in
`Amr::timeStep` (for `Amr::verbose > 0`).

Though the time is already printed out every coarse timestep
[here](https://github.com/AMReX-Codes/amrex/blob/9c256b12b89f86b30fe1a6f03dd79db351d56fb3/Src/Amr/AMReX_Amr.cpp#L2174),
with deep AMR hierarchies, it can be a long amount of [wall]time between
these printouts, hence I would find it useful to see the current
simulation time more often.

Src/Amr/AMReX_Amr.cpp

@@ -1993,7 +1993,8 @@ Amr::timeStep (int  level,
     if (verbose > 0)
     {
         amrex::Print() << "[Level " << level << " step " << level_steps[level]+1 << "] "
-                       << "ADVANCE with dt = " << dt_level[level] << "\n";
+                       << "ADVANCE at time " << time
+                       << " with dt = " << dt_level[level] << "\n";
     }
 
     Real dt_new = amr_level[level]->advance(time,dt_level[level],iteration,niter);