Make get{Line,Column}Number members of StringParser.

This patch also renames currentLocation getCurrentLocation.

llvm-svn: 288308
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index f87922c..853f426 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -1713,7 +1713,7 @@
     return readParenExpr();
 
   StringRef Tok = next();
-  std::string Location = currentLocation();
+  std::string Location = getCurrentLocation();
 
   if (Tok == "~") {
     Expr E = readPrimary();