[libFuzzer][Windows] Clean up RawPrint

Summary:
Use `_write` instead of the deprecated alias `write` on Windows.
Also, remove comment saying RawPrint is untested on Windows.

Reviewers: vitalybuka

Reviewed By: vitalybuka

Subscribers: vitalybuka

Differential Revision: https://reviews.llvm.org/D57589

llvm-svn: 353108

compiler-rt/lib/fuzzer/FuzzerIOWindows.cpp

@@ -333,8 +333,7 @@ bool IsInterestingCoverageFile(const std::string &FileName) {
 }
 
 void RawPrint(const char *Str) {
-  // Not tested, may or may not work. Fix if needed.
-  write(2, Str, strlen(Str));
+  _write(2, Str, strlen(Str));
 }
 
 }  // namespace fuzzer