texmath-0.7: tests/writers/munder-08.tex
\underset{under\ script}{\_\ baseline\ \_} = \underset{under\ script}{\overset{\phantom{fail}}{\_\ baseline\ \_}}
\underset{under\ script}{\_\ baseline\ \_} = \underset{under\ script}{\overset{\phantom{fail}}{\_\ baseline\ \_}}