35cabd69e6
As a common extension, we support the truncation of fixed-width fields
for non-list-directed input editing when a separator character (',' or
';' depending on DECIMAL='POINT' or 'COMMA' resp.) appears in the field.
This isn't working for L input editing; fix.
(The bug reports a failure with DC mode, but it doesn't work with a
comma either.)
Fixes https://github.com/llvm/llvm-project/issues/151178.