[SystemZ][z/OS] JSON file should be text files

[abhina.sreeskantharajan]

Summary

This patch sets the OF_Text flag correctly for the json file created in Clang::DumpCompilationDatabaseFragmentToDir.

[amccarth]

LGTM.

clang/lib/Driver/ToolChains/Clang.cpp

if (Err) {
     return;
   }
 
   llvm::sys::path::append(
       Path,
       Twine(llvm::sys::path::filename(Input.getFilename())) + ".%%%%.json");
   int FD;
   SmallString<256> TempPath;
-  Err = llvm::sys::fs::createUniqueFile(Path, FD, TempPath);
+  Err = llvm::sys::fs::createUniqueFile(Path, FD, TempPath,
+                                        llvm::sys::fs::OF_Text);
   if (Err) {
     Driver.Diag(diag::err_drv_compilationdatabase) << Path << Err.message();
     return;
   }
   CompilationDatabase =
       std::make_unique<llvm::raw_fd_ostream>(FD, /*shouldClose=*/true);
   DumpCompilationDatabase(C, "", Target, Output, Input, Args);
 }