[NFC][trace] Update TraceIntelPTBundleSaver.cpp to accommodate FileSpec API changes

[jj10306]

Summary

D130309 introduced changes to the FileSpec API which broke usages of
GetCString() in TraceIntelPTBundleSaver.cpp. This diff replaces usages
of GetCString() with GetPath().c_str() as suggested by D130309.

Test Plan:
Building with the trace plug-in now succeeds

[wallace]

thanks!

lldb/source/Plugins/Trace/intel-pt/TraceIntelPTBundleSaver.cpp

 ///     The threads section or \a llvm::Error in case of failures.
 static llvm::Expected<std::vector<JSONThread>>
 BuildThreadsSection(Process &process, FileSpec directory) {
   std::vector<JSONThread> json_threads;
   TraceSP trace_sp = process.GetTarget().GetTrace();
 
   FileSpec threads_dir = directory;
   threads_dir.AppendPathComponent("threads");
-  sys::fs::create_directories(threads_dir.GetCString());
+  sys::fs::create_directories(threads_dir.GetPath().c_str());
 
   for (ThreadSP thread_sp : process.Threads()) {
     lldb::tid_t tid = thread_sp->GetID();
     if (!trace_sp->IsTraced(tid))
       continue;
 
     JSONThread json_thread;
     json_thread.tid = tid;

 static llvm::Expected<llvm::Optional<std::vector<JSONCpu>>>
 BuildCpusSection(TraceIntelPT &trace_ipt, FileSpec directory, bool compact) {
   if (trace_ipt.GetTracedCpus().empty())
     return None;
 
   std::vector<JSONCpu> json_cpus;
   FileSpec cpus_dir = directory;
   cpus_dir.AppendPathComponent("cpus");
-  sys::fs::create_directories(cpus_dir.GetCString());
+  sys::fs::create_directories(cpus_dir.GetPath().c_str());
 
   for (lldb::cpu_id_t cpu_id : trace_ipt.GetTracedCpus()) {
     JSONCpu json_cpu;
     json_cpu.id = cpu_id;
     Expected<Optional<FileSpec>> context_switch_trace_path =
         WriteContextSwitchTrace(trace_ipt, cpu_id, cpus_dir, compact);
     if (!context_switch_trace_path)
       return context_switch_trace_path.takeError();