Ensure ParserOutput::getTimeProfile() is valid for all ContentHandlers

ContentHandler::getParserOutput() calls
ParserOutput::resetParseStartTime() before invoking
ContentHandler::fillParserOutput(), and then calling
ParserOutput::recordTimeProfile() on the value that returns.  This
assumes that ::fillParserOutput() mutates the ParserOutput which it is
given, instead of creating a new ParserOutput.  If you create a new
ParserOutput, you are responsible for calling ::resetParseStartTime()
on it at an appropriate point.  The various content handlers in core
respect this (poorly documented) contract, but the wikibase
ContentHandlers did not.

Bug: T376433
Change-Id: I6bba35cea2e7213fd48e5f8d25e0543695b11263

repo/includes/Content/EntityHandler.php

@@ -810,6 +810,8 @@ protected function fillParserOutput(
 	 */
 	protected function getParserOutputForRedirect( EntityContent $content, bool $generateHtml ) {
 		$parserOutput = new ParserOutput();
+		$parserOutput->resetParseStartTime();
+
 		$target = $content->getRedirectTarget();
 
 		// Make sure to include the redirect link in pagelinks

repo/includes/ParserOutput/FullEntityParserOutputGenerator.php

@@ -85,6 +85,7 @@ public function getParserOutput(
 		$entity = $entityRevision->getEntity();
 
 		$parserOutput = new ParserOutput();
+		$parserOutput->resetParseStartTime();
 
 		$updaterCollection = new EntityParserOutputDataUpdaterCollection( $parserOutput, $this->dataUpdaters );
 		$updaterCollection->updateParserOutput( $entity );