## Motivation
Improve accuracy of conv bwd data perf measurements
## Technical Details
- enable flush cache
- for grouped conv we zero conv input(gemm output) inside device op, so
we also include this in time measurement
- for non-grouped conv we zero conv input(gemm output) outside device op
(in profile_conv_bwd_data_impl.hpp) so it is not included.
- In this pr I changed it to include zeroing if time_kernel/flush cache
is enabled so at now you should have more fair comparison. I changed it
only for time_kernel/flush_cache because MIOpen run own zeroing for
non-grouped solvers.
## Test Plan
test_grouped_conv_bwd_data_*
## Test Result
CI pending
## Submission Checklist
- [x] Look over the contributing guidelines at
https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.
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