Use HashMap for DexFileVerifier

Before:
2.51%  std::map<unsigned int, unsigned short>::insert(...
0.72%  malloc

After:
0.73%  art::HashSet<std::__1::pair<unsigned int, unsigned short>::Insert(...
0.57%  malloc

The allocation from HashSet is only 0.71% of the remaining 0.57% malloc time.
0.71% art::DexFileVerifier::CheckIntraSectionIterate(unsigned long, unsigned int, unsigned short)

Bug: 10921004

Change-Id: I85c60bf27fb2d9976b944fc15d8401904432dc22