Fix dumpio: true logs about Script terminated by timeout

[timvandermeij]

In PR #18260 we enabled dumpio: true for Puppeteer. This option forwards the browser logs to Node's log stream so that we can see any warnings/errors that are logged in e.g. the web console. This surfaced a few interesting issues that we should fix before we enable that further due to the spammy nature of said logs.

This issue tracks the following often repeated log from http://54.241.84.105:8877/34fcd127eefeaf9/output.txt:

JavaScript warning: http://127.0.0.1:41223/build/generic/web/viewer.mjs, line 5808: Script terminated by timeout at:
#pageHide@http://127.0.0.1:41223/build/generic/web/viewer.mjs:5808:3
EventListener.handleEvent*#bindEvents@http://127.0.0.1:41223/build/generic/web/viewer.mjs:5823:12
initialize@http://127.0.0.1:41223/build/generic/web/viewer.mjs:5458:21
_initializePdfHistory@http://127.0.0.1:41223/build/generic/web/viewer.mjs:13144:21
load/</<@http://127.0.0.1:41223/build/generic/web/viewer.mjs:12889:14
promise callback*load/<@http://127.0.0.1:41223/build/generic/web/viewer.mjs:12887:109

Note that this particular traceback, in #pageHide, is most common, but there are also tracebacks that occur in other places with the same termination warning.

We should find out why this is logged after pretty much every test.

[Snuffleupagus]

Maybe after each integrationtest, before closing the tab, we could run (and await) PDFViewerApplication.close() since I believe that doing so would avoid these warnings.