Re-enable MSVC++ C4389 warning in CmdHelperEq()
Re-enable MSVC++ C4389 warning in CmdHelperEq()

C4389 was inhibited in commit 4b83461 making behavior inconsistent with
other compilers.

xnagireddy/googletest,empiredan/googletest,google/googletest,antidotcb/googletest,jlanecox/googletest,empiredan/googletest,antidotcb/googletest,fuchsia-mirror/third_party-googletest,xnagireddy/googletest,google/googletest,jlanecox/googletest,xnagireddy/googletest,empiredan/googletest,fuchsia-mirror/third_party-googletest,antidotcb/googletest,google/googletest,antidotcb/googletest,google/googletest,fuchsia-mirror/third_party-googletest,fuchsia-mirror/third_party-googletest,jlanecox/googletest,gianricardo/googletest,gianricardo/googletest,jlanecox/googletest,gianricardo/googletest,xnagireddy/googletest