Don't perform a microtask checkpoint for document.write('<script><\/script>')

Source/core/html/parser/HTMLScriptRunner.cpp

Index: Source/core/html/parser/HTMLScriptRunner.cpp
diff --git a/Source/core/html/parser/HTMLScriptRunner.cpp b/Source/core/html/parser/HTMLScriptRunner.cpp
index 535d621752ff6d7c547c49b5d9cb458dda8de535..2d73cce4c81cdda555d589f2690692f29055aef1 100644
--- a/Source/core/html/parser/HTMLScriptRunner.cpp
+++ b/Source/core/html/parser/HTMLScriptRunner.cpp
@@ -288,7 +288,8 @@ void HTMLScriptRunner::runScript(Element* script, const TextPosition& scriptStar
 
         ASSERT(scriptLoader->isParserInserted());
 
-        Microtask::performCheckpoint();
+        if (!isExecutingScript())
+            Microtask::performCheckpoint();
 
         InsertionPointRecord insertionPointRecord(m_host->inputStream());
         NestingLevelIncrementer nestingLevelIncrementer(m_scriptNestingLevel);