refactor: replace reflect.TypeOf dispatch in exit handlers with type switch (task 432)

The exitHandlers map keyed by reflect.Type was a reflection-based dispatch
table that incurred allocation and reflection overhead on every event pair
in the hot processing path. Replace it with a plain type switch in
handleTracepointExit, which the compiler resolves statically.

Removes: initExitHandlers, typeKey, mustBeType, newTypedExitHandler,
exitHandlerRegistry, the exitHandlers struct field, and the tracepointExitHandler
type alias — all dead after the switch. Fixes a pre-existing uint→uint64
mismatch in stats(). Updates tests to target the new default branch directly.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

0 files changed, 0 insertions, 0 deletions