Internal coverage: Fix some test runs having conflicting sources.

test_regress/driver.pl

@@ -1362,7 +1362,6 @@ sub execute {
                     %param,
                     expect=>$param{expect},  # backward compatible name
                     expect_filename=>$param{expect_filename},  # backward compatible name
-                    verilator_run => 1,
                     );
     }
     else {

test_regress/t/t_gantt.pl

@@ -40,7 +40,6 @@ run(cmd => ["$ENV{VERILATOR_ROOT}/bin/verilator_gantt",
             "$Self->{obj_dir}/profile_threads.dat",
             "--vcd $Self->{obj_dir}/profile_threads.vcd",
             "| tee $Self->{obj_dir}/gantt.log"],
-    verilator_run => 1,
     );
 
 file_grep("$Self->{obj_dir}/gantt.log", qr/Total threads += 2/i);