[dvsim] Make sure results_html_name key is defined
[dvsim] Make sure results_html_name key is defined

Signed-off-by: Michael Schaffner <a005a2d3342a687ea2d05360c953107acbe83e08@google.com>

AmbiML/ibex,AmbiML/ibex,lowRISC/ibex,AmbiML/ibex,lowRISC/ibex,AmbiML/ibex,lowRISC/ibex,lowRISC/ibex