Creating an IBMDB2I table with the macce character set
is successful, but any attempt to insert data into the
table was failing.

This was happening because the character set name "macce"
is not a valid iconv descriptor for IBM i PASE. This patch
adds an override to convertTextDesc to use the equivalent
valid iconv descriptor "IBM-1282" instead.

mysql-test/suite/ibmdb2i/r/ibmdb2i_bug_45793.result:
  Bug#45793 macce charset causes error with IBMDB2I
  
  Result file for the test case.
mysql-test/suite/ibmdb2i/t/ibmdb2i_bug_45793.test:
  Bug#45793 macce charset causes error with IBMDB2I
  
  Add a testcase for the macce charater set.
storage/ibmdb2i/db2i_charsetSupport.cc:
  Bug#45793 macce charset causes error with IBMDB2I
  
  The character set name "macce" is not a valid iconv
  descriptor for IBM i PASE. Add an override to convertTextDesc
  to use the equivalent valid iconv descriptor "IBM-1282" 
  instead.