[FileSpec] Delegate common operations to llvm::sys::path

With the recent changes in FileSpec to use LLVM's path style, it is
possible to delegate a bunch of common path operations to LLVM's path
helpers. This means we only have to maintain a single implementation and
at the same time can benefit from the efforts made by the rest of the
LLVM community.

This is part one of a set of patches. There was no obvious way to split
this so I just worked from top to bottom.

Differential revision: https://reviews.llvm.org/D48084

llvm-svn: 334615

lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

@@ -2047,8 +2047,8 @@ unsigned ObjectFileELF::ParseSymbols(Symtab *symtab, user_id_t start_id,
   // custom extension and file name makes it highly unlikely that this will
   // collide with anything else.
   ConstString file_extension = m_file.GetFileNameExtension();
-  bool skip_oatdata_oatexec = file_extension == ConstString("oat") ||
-                              file_extension == ConstString("odex");
+  bool skip_oatdata_oatexec = file_extension == ConstString(".oat") ||
+                              file_extension == ConstString(".odex");
 
   ArchSpec arch;
   GetArchitecture(arch);