Add the vba ppt sample to the `find_vba` list in the `test_macros` function.

[kijeong]

This pull request is related to #859 and #723. I made some additional adjustments to the changes from #859. @christian-intra2net, it would be great if you could review it.

The file 'olevba/sample_with_vba.ppt' contains an actual VBA macro.

And in my opinion, the code page should not vary depending on the test machine.

I referred to the following parts:

• olefile.py:OleFileIO.getproperties function

  • property_id: 1, value: 949

• codepages.py:get_codepage_name, CODEPAGE_NAME[949]