add static_cast to get rid of warnings for intel compiler on linux platform
add static_cast to get rid of warnings for intel compiler on linux platform

nickhutchinson/benchmark-cxx03,eliben/benchmark,eliben/benchmark,google/benchmark,nickhutchinson/benchmark,nickhutchinson/benchmark-cxx03,disconnect3d/benchmark,codygray/benchmark,nickhutchinson/benchmark-cxx03,efcs/benchmark,ntx-/benchmark,google/benchmark,xlqian/benchmark,disconnect3d/benchmark,LepelTsmok/benchmark,ntx-/benchmark,LepelTsmok/benchmark,disconnect3d/benchmark,chemhack/benchmark,efcs/benchmark,mockingbirdnest/benchmark,ntx-/benchmark,fuchsia-mirror/third_party-benchmark,nickhutchinson/benchmark,fuchsia-mirror/third_party-benchmark,eliben/benchmark,everbase/benchmark,xlqian/benchmark,fuchsia-mirror/third_party-benchmark,fuchsia-mirror/third_party-benchmark,chemhack/benchmark,nickhutchinson/benchmark,mockingbirdnest/benchmark,nickhutchinson/benchmark,everbase/benchmark,chemhack/benchmark,eliben/benchmark,codygray/benchmark,everbase/benchmark,LepelTsmok/benchmark,disconnect3d/benchmark,efcs/benchmark,efcs/benchmark,everbase/benchmark,mockingbirdnest/benchmark,nickhutchinson/benchmark-cxx03,google/benchmark,mockingbirdnest/benchmark,codygray/benchmark,LepelTsmok/benchmark,xlqian/benchmark,xlqian/benchmark,ntx-/benchmark,codygray/benchmark,chemhack/benchmark