Java Units: Add more cases of dimensional analysis for `times()` and `divide()`

[bhall-ctre]

This adds/fixes some common cases of dimensional analysis for times() and divide() in the Java units library:

• Dimensionless * U -> U
• Dimensionless * Per<U, Dimensionless> -> U
• Time * Velocity<U> -> U
• Dimensionless / Velocity<U> -> Per<Time, U>
• Dimensionless / Per<U1, U2> -> Per<U2, U1>
• Dimensionless / Per<Time, U> -> Velocity<U>
• U / Time -> Velocity<U>

This does not add dimensional analysis when one of the measurements is a Mult<U1, U2>.