Change Details

``` Several places in the codebase use the fast range mapping technique described in https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/, some for 32-bit ranges, some for 64-bit ones. Move all of these to util/fastrange.h, and give them a consistent name. ``` Backport of core#23994.

``` Several places in the codebase use the fast range mapping technique described in https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/, some for 32-bit ranges, some for 64-bit ones. Move all of these to util/fastrange.h, and give them a consistent name. ``` Backport of [[https://github.com/bitcoin/bitcoin/pull/23994 | core#23994]].

``` Several places in the codebase use the fast range mapping technique described in https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/, some for 32-bit ranges, some for 64-bit ones. Move all of these to util/fastrange.h, and give them a consistent name. ``` Backport of [[https://github.com/bitcoin/bitcoin/pull/23994 | core#23994]].