Fixes#6106
To avoid future regressions, two new unit tests were added:
1. A new PDF based on the report from #6106, which contains an
OpenAction of type JavaScript and a string "this.print({...}".
2. An existing PDF from https://bugzil.la/1001080 (from #4698).
Although it does not matter, since we don't execute the JavaScript code,
I have also changed "print(true)" to "print({})" since the print method
takes an object (not a boolean). See "Printing PDF documents", page 62:
http://adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/js_developer_guide.pdf
Doing this helped uncover an issue with the `getDestination` implementation.
Currently if a named destination doesn't exist, the method (in `obj.js`) may return `undefined` which leads to the promise being stuck in a pending state.
*Note:* returning `null` for this case is consistent with other methods, e.g. `getOutline` and `getAttachments`.
The patch adds a test to ensure that `getStats` returns the expected result after the page has been parsed, and cleans up the existing test a bit.
Also, since I'm touching the file anyway, I'm making a small adjustment of the `getDownloadInfo` test. (I have no idea why I didn't just write it like this initially.)
The 'Version' field of the most recent document catalog, if present, is
intended to supersede the value in the file prologue.
This is significant for incrementally-built PDF documents and generators that
emit a low version in the prologue and later apply a format version based on
PDF features used, such as Apple's CoreGraphics/Quartz PDF backend.
Fixes the internal version variable, as well as the PDFFormatVersion reported
by the API and consumed by viewers.
As a follow-up to PR #4795, this patch improves the `getData` unit test to ensure that the returned data is of the expected type and of the correct length.
