Correctly keep track of isolates for microtask execution

BUG=487155
R=haraken@chromium.org

Review URL: https://codereview.chromium.org/1161823002

git-svn-id: svn://svn.chromium.org/blink/trunk@195985 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DEFINE_TRACE(HTMLScriptRunner)
{
    visitor->trace(m_document);
    visitor->trace(m_host);
    visitor->trace(m_parserBlockingScript);
#if ENABLE(OILPAN)
    visitor->trace(m_scriptsToExecuteAfterParsing);
#endif
}

DEFINE_TRACE(HTMLScriptRunner)
{
    visitor->trace(m_document);
    visitor->trace(m_host);
    visitor->trace(m_parserBlockingScript);
#if ENABLE(OILPAN)
    visitor->trace(m_scriptsToExecuteAfterParsing);
#endif
}
