Enclosed is v3 of this patch; this adds two modes for this feature,
one with the raw page `--save-fullpage/-W` and one with the
LSN+checksum fixups `--save-fullpage-fixup/-X`.
I've added at least some basic sanity-checking of the underlying
feature, as well as run the test file and the changes to pg_waldump.c
through pgindent/perltidy to make them adhere to project standards.
Threw in a rebase as well.
Would appreciate any additional feedback here.
Best,
David