This patch removes unused `USE_REPORT_PRELUDE` code paths from the
tree. They have been present since the first git revision
4fb94ae5, and might have been useful
for debugging purposes many years ago, but these code paths are never
actually built. Removing these ease maintenance of relevant modules in
the future, and also allows us to get rid of `CPP` extension in those
modules as a nice byproduct.

(cherry picked from commit 573cad4b)