handle CMAP format 0 for platform 1, encoding 0 (legacy Macintosh encoding)

[Connum]

Description

Adds support for Macintosh encoding in the form of CMAP table format 0 with platformId 1 and encodingId 0.

Motivation and Context

Although deprecated, older fonts may still use this encoding format.
The CMAP-3 test case of the unicode test tool failed for Opentype.js and didn't show any glyphs at all. The tests are still not marked as conformant after this PR due to small decimal rounding differences, but that is a separate issue and visually the glyphs render OK.

How Has This Been Tested?

Added tests, ran the unicode test tool with the local dev branch and compared the outlines.

Screenshots (if appropriate):

unicode test tool test case CMAP-3 before:

unicode test tool test case CMAP-3 after:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I did npm run test and all tests passed green (including code styling checks).
• I have added tests to cover my changes.
• My change requires a change to the documentation.
• I have updated the README accordingly.
• I have read the CONTRIBUTING document.