Back out changes in a generated file

Author: AaronBallman

clang/lib/Tooling/Inclusions/Stdlib/CSymbolMap.inc

@@ -389,7 +389,6 @@ SYMBOL(cosh, None, <math.h>)
 SYMBOL(coshf, None, <math.h>)
 SYMBOL(coshl, None, <math.h>)
 SYMBOL(cosl, None, <math.h>)
-SYMBOL(countof, None, <stdcountof.h>)
 SYMBOL(cpow, None, <complex.h>)
 SYMBOL(cpowf, None, <complex.h>)
 SYMBOL(cpowl, None, <complex.h>)