Fix RangeError when decoding base64

[filipefigcorreia]

This PR fixes a RangeError: Invalid array length error that can be thrown when decoding a Base64Binary.

It may also be worth to look into the latest version of the Base64Binary code that this was based on, and which is available here (and that was first introduced in this blog post).

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Edit: On closer inspection, the value that I was trying to decode seems to be truncated/incomplete. Still, it may be worth to update the Base64Binary code to the one that I have linked to, as jsonix currently fails with an unclear error if can't decode a base64 value. For reference, this is the "weird" base64 value that I was trying to decode: BwABBJQ1gJDUCAAAAAAA=

[highsource]

I've applied your fix to the right place and added a test case.
I'm a bit reluctant to use the code you linked to as it uses typesafe arrays which aren't quite vanilla JS from my point of view.

[filipefigcorreia]

Thanks.

I'm a bit reluctant to use the code you linked to as it uses typesafe arrays which aren't quite vanilla JS from my point of view.

I can live with this :-)