ReactorBenchmarks.cpp was accidentally moved to the wrong location as
part of swiftshader-cl/50388.

Bug: b/173404759
Change-Id: I4c0f836ddb7729d6d4409fe757d384cadb5b48b3
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51289Tested-by: Antonio Maiorano <amaiorano@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>