[clang][Tooling] Delete dots and dotdots when generating absolute paths

[kadircet]

Summary

GetAllFiles interface returns absolute paths, but keeps dots and dot
dots. This patch makes those paths canonical by deleting them.

[hokein]

lib/Tooling/JSONCompilationDatabase.cpp

373

nit: add the /*remove_dot_dot=*/ for the true parameter.

lib/Tooling/JSONCompilationDatabase.cpp

for (auto &NextObject : *Array) {
     SmallString<8> FileStorage;
     StringRef FileName = File->getValue(FileStorage);
     SmallString<128> NativeFilePath;
     if (llvm::sys::path::is_relative(FileName)) {
       SmallString<8> DirectoryStorage;
       SmallString<128> AbsolutePath(
           Directory->getValue(DirectoryStorage));
       llvm::sys::path::append(AbsolutePath, FileName);
+      llvm::sys::path::remove_dots(AbsolutePath, true);
       llvm::sys::path::native(AbsolutePath, NativeFilePath);
     } else {
       llvm::sys::path::native(FileName, NativeFilePath);
     }
     auto Cmd = CompileCommandRef(Directory, File, *Command, Output);
     IndexByFile[NativeFilePath].push_back(Cmd);
     AllCommands.push_back(Cmd);
     MatchTrie.insert(NativeFilePath);
   }
   return true;
 }

unittests/Tooling/CompilationDatabaseTest.cpp

EXPECT_EQ(std::vector<std::string>(),
       << ErrorMessage;
 
   std::vector<std::string> expected_files;
   SmallString<16> PathStorage;
   llvm::sys::path::native("//net/dir/file1", PathStorage);
   expected_files.push_back(PathStorage.str());
   llvm::sys::path::native("//net/dir/file2", PathStorage);
   expected_files.push_back(PathStorage.str());
+  llvm::sys::path::native("//net/file1", PathStorage);
+  expected_files.push_back(PathStorage.str());
   EXPECT_EQ(expected_files,
             getAllFiles("[{\"directory\":\"//net/dir\","
                         "\"command\":\"command\","
                         "\"file\":\"file1\"},"
                         " {\"directory\":\"//net/dir\","
                         "\"command\":\"command\","
+                        "\"file\":\"../file1\"},"
+                        " {\"directory\":\"//net/dir\","
+                        "\"command\":\"command\","
                         "\"file\":\"file2\"}]",
                         ErrorMessage, JSONCommandLineSyntax::Gnu))
       << ErrorMessage;
 }
 
 TEST(JSONCompilationDatabase, GetAllCompileCommands) {
   std::string ErrorMessage;
   EXPECT_EQ(