Tweak the MMType1 font detection in `getFontFileType` to improve font telemetry (PR 9961 follow-up)
Tweak the MMType1 font detection in `getFontFileType` to improve font telemetry (PR 9961 follow-up)

Please note that this patch does *not* affect rendering in any way, however it's relevant for font telemetry[1].

According to the specification, see https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf#G8.1904956, Type1C is a valid subtype for *both* Type1 and MMType1 fonts.

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[1] Refer to the font telemetry results in https://telemetry.mozilla.org/new-pipeline/dist.html#!cumulative=0&end_date=2018-06-25&keys=__none__!__none__!__none__&max_channel_version=nightly%252F62&measure=PDF_VIEWER_FONT_TYPES&min_channel_version=nightly%252F59&processType=*&product=Firefox&sanitize=1&sort_keys=submissions&start_date=2018-05-07&table=0&trim=1&use_submission_date=0

See also https://github.com/mozilla/pdf.js/wiki/Enumeration-Assignments-for-the-Telemetry-Histograms#pdf_viewer_font_types for help with interpreting the data.

Snuffleupagus/pdf.js,caremerge/pdf.js,macroplant/pdf.js,nawawi/pdf.js,mukulmishra18/pdf.js,mainegreen/pdf.js,timvandermeij/pdf.js,caremerge/pdf.js,mozilla/pdf.js,mozilla/pdf.js,timvandermeij/pdf.js,showpad/mozilla-pdf.js,showpad/mozilla-pdf.js,showpad/mozilla-pdf.js,Shoobx/pdf.js,mukulmishra18/pdf.js,mozilla/pdf.js,macroplant/pdf.js,Shoobx/pdf.js,xavier114fch/pdf.js,Snuffleupagus/pdf.js,nawawi/pdf.js,timvandermeij/pdf.js,macroplant/pdf.js,xavier114fch/pdf.js,mainegreen/pdf.js,nawawi/pdf.js,Snuffleupagus/pdf.js,Shoobx/pdf.js