[c10d] fix the macro definition of NCCL_COMM_DUMP (#120502)
Summary:
Only if both macros are defined, should we dump the comm dump,
otherwise, use the original definition.
The previous implementation missed the function definition when IS_NCCL_EXP is defined but NCCL_COMM_DUMP is not defined
Test Plan:
Build and unit test
Pull Request resolved: https://github.com/pytorch/pytorch/pull/120502
Approved by: https://github.com/dsjohns2, https://github.com/Skylion007
