yaz 5.4.2
yaz: recommend depending on icu4c

as discussed in #31830

Also:

* add test for yaz-icu when building with ICU
* do not use File.open for writing test configuration files
yaz: update 5.4.2 bottle.

Closes #32261.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>