report.html: add details about mozmill test errors
report.html: add details about mozmill test errors

boklm/tbb-testsuite,gunesacar/tor-browser-bundle-testsuite,gunesacar/tor-browser-bundle-testsuite,boklm/tbb-testsuite,boklm/tbb-testsuite,gunesacar/tor-browser-bundle-testsuite,boklm/tbb-testsuite,boklm/tbb-testsuite,gunesacar/tor-browser-bundle-testsuite