Code generation for character intervals incorrectly calculates lower bound
for else-part subinterval. This subinterval is included in "switch" IL
instruction, but its lower index is off by 1. The "switch" instruction
should start at '%/51/' and include all indexes up to '%/62/', but in
actual code the instruction starts at '%/50/'.

Discovered in release 5.6.0530 for .NET code generation.