add build flag for rocblas tune and fix bug (#14797)
### Description
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1. add a build flag for rocblas tuning feature.
2. fix a build bug when enable rocblas tuning.
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
The rocblas tunning feature has no build flag to control, only using a
MACRO flag.
So I add an build flag, and fix a code bug when enable rocblas tunning.
