Fix a name-hiding issue in WhileDoStmt that generated a warning/error under LLVM
Merge pull request #867 from noakesmichael/llvm-bug

The LLVM configuration generates a name-hiding warning/error that is overlooked by the other compiler modes.
Updated one of the usages to resolve.

Compiled STD clang/darwin, STD gcc/linux64, LLVM gcc/linux
Test: Not directly tested but another test is running currently with this patch applied
Review: None