apacheGH-15200: [C++] Created benchmarks for round kernels. (apache#1…

…5201)

The four existing kernel functions Ceil, Floor, Round, and Trunc gain benchmarks with this change.
* Closes: apache#15200

Lead-authored-by: David Sisson <EpsilonPrime@users.noreply.github.com>
Co-authored-by: Will Jones <willjones127@gmail.com>
Signed-off-by: Yibo Cai <yibo.cai@arm.com>

cpp/src/arrow/compute/kernels/scalar_round_benchmark.cc

@@ -109,7 +109,7 @@ static void Trunc(benchmark::State& state) {
   DECLARE_ROUND_BENCHMARKS_WITH_ROUNDMODE(OP, UInt16Type); \
   DECLARE_ROUND_BENCHMARKS_WITH_ROUNDMODE(OP, UInt8Type);  \
   DECLARE_ROUND_BENCHMARKS_WITH_ROUNDMODE(OP, FloatType);  \
-  DECLARE_ROUND_BENCHMARKS_WITH_ROUNDMODE(OP, DoubleType)
+  DECLARE_ROUND_BENCHMARKS_WITH_ROUNDMODE(OP, DoubleType);
 
 DECLARE_ROUND_BENCHMARKS(Ceil);
 DECLARE_ROUND_BENCHMARKS(Floor);