... and move them to where they are really needed.
This was found by IWYU:
txmempool.h should remove these lines:
- #include <random.h> // lines 29-29
- class CBlockIndex; // lines 43-43
- class Chainstate; // lines 45-45
Also, move the stdlib section to the right place. Can be reviewed with:
--color-moved=dimmed-zebra
Since the kernel library no longer depends on the system file, move it
to the common library instead in accordance to the diagram in
doc/design/libraries.md.
