sim_if/nvc.py: quote words with spaces in printed command (#940)

This allows the command to be directly copied and pasted without having
to quote e.g. the JSON in the `-g` argument.

Author: nickg

docs/news.d/940.misc.rst

@@ -0,0 +1 @@
+[NVC] Multi-word command line arguments are now quoted in the log.

vunit/sim_if/nvc.py

@@ -275,7 +275,7 @@ def simulate(self, output_path, test_suite_name, config, elaborate_only):
             if wave_file:
                 cmd += [f"--wave={wave_file}"]
 
-        print(" ".join(cmd))
+        print(" ".join([f"'{word}'" if " " in word else word for word in cmd]))
 
         status = True