Revert "ADT: correctly report isMSVCEnvironment for windows itanium"

This reverts commit r222180.

llvm-svn: 222188
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
index d6dab53..5a9181d 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.cpp
@@ -270,7 +270,7 @@
   } else if (TheTriple.isOSBinFormatELF()) {
     // Force the use of an ELF container.
     MAI = new X86ELFMCAsmInfo(TheTriple);
-  } else if (TheTriple.isKnownWindowsMSVCEnvironment()) {
+  } else if (TheTriple.isWindowsMSVCEnvironment()) {
     MAI = new X86MCAsmInfoMicrosoft(TheTriple);
   } else if (TheTriple.isOSCygMing() ||
              TheTriple.isWindowsItaniumEnvironment()) {