patch 8.2.0343: Vim9: using wrong instruction, limited test coverage

Problem:    Vim9: using wrong instruction, limited test coverage.
Solution:   Use ISN_PUSHJOB.  Add a few more tests.
diff --git a/src/vim9execute.c b/src/vim9execute.c
index be19b1f..094ee72 100644
--- a/src/vim9execute.c
+++ b/src/vim9execute.c
@@ -1915,7 +1915,7 @@
 		    tv.v_type = VAR_JOB;
 		    tv.vval.v_job = iptr->isn_arg.job;
 		    name = tv_get_string(&tv);
-		    smsg("%4d PUSHJOB %s", current, name);
+		    smsg("%4d PUSHJOB \"%s\"", current, name);
 		}
 #endif
 		break;