[TeX] \left...\right can introduce unwanted inferred mrows
This commit introduces unwanted inferred mrows into \left...\right
constructions when there is more than one element within the delimiters. E.g., \left( x x \right)
will end up with an mrow
containing three children: the mo
for the open paren, an inferred mrow
containing the two mi
for the x's, and the mo
for the close paren.
The inferred mrow should be unpacked; just not explicit mrows. The linked commit was too aggressive, and fails to unpack these inferred rows.