Reg Tests: XML 01b has an incorrect number of measures

Reg Tests: XML 01b has an incorrect number of measures

Issue 3973

01b-Pitches-Intervals.xml from the Unofficial MusicXML
test suite contains only a single measure in MusicXML,
but there should be 41.

musicxml2ly is very tolerant here so the error doesn’t
show in the pdf.

Added missing <measure> elements
Fixed a typo in the title
Added missing <accidental> elements (They represent
the actual notated accidentals.  Without these elements
there shouldn’t be any visible accidentals. So this is
actually a bug in musicxml2ly. The bug doesn’t show here
because musicxml2ly interprets the <alter> element which
represents the sounding pitch of a note.)

Fixes provided by Patrick Schmidt