Print physical file path when checksum check fails

Hi hacker,

Currently we only print block number and relation path when checksum check
fails. See example below:

ERROR: invalid page in block 333571 of relation base/65959/656195

DBA complains that she needs additional work to calculate which physical
file is broken, since one physical file can only contain `RELSEG_SIZE`
number of blocks. For large tables, we need to use many physical files with
additional suffix, e.g. 656195.1, 656195.2 ...

Is that a good idea to also print the physical file path in error message?
Like below:

ERROR: invalid page in block 333571 of relation base/65959/656195, file
path base/65959/656195.2

Patch is attached.
--
Thanks

Hubert Zhang