Replace all uses of PathV1::isAbsolute with PathV2::is_{absolute,relative}.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@122087 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Frontend/InitHeaderSearch.cpp b/lib/Frontend/InitHeaderSearch.cpp
index 438556e..5bae3ea 100644
--- a/lib/Frontend/InitHeaderSearch.cpp
+++ b/lib/Frontend/InitHeaderSearch.cpp
@@ -106,10 +106,10 @@
   // Compute the actual path, taking into consideration -isysroot.
   llvm::SmallString<256> MappedPathStorage;
   llvm::StringRef MappedPathStr = Path.toStringRef(MappedPathStorage);
-  llvm::sys::Path MappedPath(MappedPathStr);
 
   // Handle isysroot.
-  if (Group == System && !IgnoreSysRoot && MappedPath.isAbsolute() &&
+  if (Group == System && !IgnoreSysRoot &&
+      llvm::sys::path::is_absolute(MappedPathStr) &&
       IncludeSysroot != llvm::sys::Path::GetRootDirectory()) {
     MappedPathStorage.clear();
     MappedPathStr =