dyncom: Remove two huge global arrays of std::map

Dyncom had two global array that together allocated 128K instances of
std::map during startup. They appear to be related to the dynamic
compilation support and thus are currently unused in Citra. If they need
to be reintroduced in the future, a more performant way of storing this
data should be used.

This removes a long (~12s) delay during process shutdown when using the
Windows Debug heap, as well as reducing memory usage by 8MB.