[BOLT][NFC] Drop MMap events for deleted files

[Amir]

Summary

Don't parse/handle mmap events with "(deleted)" filename.

[rafauler]

Where does this happen?

[Amir]

I observed that with perf data here: https://github.com/rafaelauler/bolt-tests/blob/main/test/X86/perf2bolt-multiple-edge.test#L13
Not sure how common is that, but "(deleted)" shows up in a couple of places in kernel, notably as DSO__DELETED in linux/tools/perf/util/map.c: https://github.com/search?q=repo%3Atorvalds%2Flinux%20%22(deleted)%22&type=code

bolt/lib/Profile/DataAggregator.cpp

std::error_code DataAggregator::parseMMapEvents() {
   while (hasData()) {
     ErrorOr<std::pair<StringRef, MMapInfo>> FileMMapInfoRes = parseMMapEvent();
     if (std::error_code EC = FileMMapInfoRes.getError())
       return EC;
 
     std::pair<StringRef, MMapInfo> FileMMapInfo = FileMMapInfoRes.get();
     if (FileMMapInfo.second.PID == -1)
       continue;
+    if (FileMMapInfo.first.equals("(deleted)"))
+      continue;
 
     // Consider only the first mapping of the file for any given PID
     auto Range = GlobalMMapInfo.equal_range(FileMMapInfo.first);
     bool PIDExists = llvm::any_of(make_range(Range), [&](const auto &MI) {
       return MI.second.PID == FileMMapInfo.second.PID;
     });
 
     if (PIDExists)