benchmark

Bug fix variable 'actual_iterations' set but not used (#1517)

* Bug fix variable 'actual_iterations' set but not used

Compiling the project in clang 15 without -Wno-unused-but-set-variable flag the following error is generated:

benchmark-src/test/options_test.cc:70:10: error: variable 'actual_iterations' set but not used [-Werror,-Wunused-but-set-variable]
  size_t actual_iterations = 0;
         ^

* Adjust according formatting of `clang-format`

Co-authored-by: dominic hamon <510002+dmah42@users.noreply.github.com>