[CodeGen] Prune headers and move code out of line for build efficiency, NFC (#135622)

I noticed these destructors taking time with -ftime-trace and moved some
of them for minor build efficiency improvements.

The main impact of moving destructors out of line is that it avoids
requiring container fields containing other types from being complete,
i.e. one can have uptr<T> or vector<T> as a field with an incomplete
type T, and that means we can reduce transitive includes, as with
LegalizerInfo.h.

Move expensive getDebugOperandsForReg template out-of-line. The
std::function instantiation shows up in time trace even if you don't use
the function.

0 files changed, 0 insertions, 0 deletions