MORX-32: Insertion At Mark Without SetMark

The font for this test case has an AAT Extended Glyph Metamorphosis Table with a single Glyph Insertion Subtable. Its finite-state machine contains the following transitions:

For glyph A, the transition inserts the string INS before the currently marked glyph.
For glyph B, the transition inserts the string INS after the currently marked glyph.
For any other glyphs and “end of text”, the transition carries no flags and performs no insertions.

The test cases check what happens when inserting glyphs without setting the mark. We expect that implementations match the buggy behavior of Apple’s CoreText, since the existing fonts have been developed for that platform. See also HarfBuzz bug 1195.

	A	XAY	B	XBY
Expected
Observed
Conformance