TEST ONLY -- Verify behavior of DISP_E_BADINDEX in the IE JavaScript runtime

TEST ONLY -- Verify behavior of DISP_E_BADINDEX in the IE JavaScript runtime

This change set is not intended to be committed. It's a live test of how the
JavaScript engine in IE interprets DISP_E_BADINDEX when returned from our
injected 'Settings' object. The result is that the statement throws an
exception with message "Subscript out of range", and the 'name' property on
its prototype object is "RangeError".

The result: returning DISP_E_BADINDEX is fully supported by JavaScript in IE.

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Add a test method to 'CPluginUserSettings' named "TestBadIndex". When passed
zero, it returns normally, to verify that this method can be called. When
passed any positive number, it returns DISP_E_BADINDEX.

Add HTML and JS test files. The HTML test page is located in "html/templates"
to ensure settings injection.

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Informs the following review:
    https://codereview.adblockplus.org/29330798/

[Oleksandr, 2015-12-03 12:03:35]

Have you tried this on older version of IE as well? We know that
DISP_E_EXCEPTION with pExcepInfo = NULL is not causing any problems. I am not
sure there's enough incentive to change the return value.

[Eric, 2015-12-03 13:37:00]

On 2015/12/03 12:03:35, Oleksandr wrote:
> Have you tried this on older version of IE as well?

No.

RangeError, however, has been in javascript for a long time. I can't find
anything on it being a compatibility problem on, say, quirksmode or caniuse. It
seems possible that Microsoft suddenly woke up for IE 9 and said "OMG we never
implemented RangeError for ActiveX!" but I really doubt that, since Microsoft's
original business strategy was to blunt the web by making it an ActiveX
container for corporate intranets.