Move folly/Benchmark.h from test/FBVectorTestUtil.h to test/FBVectorBenchmark

Summary: As far as I can tell, folly/test/FBVectorTestUtil.h does not need to include folly/Benchmark.h. Move it to folly/testFBVectorBenchmark where it is actually used.

Reviewed By: yfeldblum

Differential Revision: D16931137

fbshipit-source-id: 8ef5f99a783537672d55883adadd08270e318a61

folly/test/FBVectorBenchmark.cpp

@@ -22,6 +22,7 @@
 #include <memory>
 #include <string>
 
+#include <folly/Benchmark.h>
 #include <folly/FBVector.h>
 #include <folly/Traits.h>
 #include <folly/container/Foreach.h>

folly/test/FBVectorTestUtil.h

@@ -20,7 +20,6 @@
 #include <list>
 #include <random>
 
-#include <folly/Benchmark.h>
 #include <folly/FBString.h>
 #include <folly/Random.h>
 #include <folly/portability/GTest.h>