fix mis-traversal on addrvars caused by iterator invalidation in conn…

[clingfei]

Insert to unordered_set will cause iterator invalidation once rehash occurred.

This will result in fewer PARAMETER_IN edges being generated than actually.

For example，when I use PDG to analyze function ixgbe_intr in ixgbe.ko.ll, the actual addr_var of arg %1 is :

  %205 = getelementptr inbounds i8, i8* %1, i64 5904, !dbg !133988
  %159 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133962
  %141 = getelementptr inbounds i8, i8* %1, i64 544, !dbg !133934
  %193 = getelementptr inbounds i8, i8* %1, i64 6160, !dbg !133982
  %3 = bitcast i8* %1 to %struct.ixgbe_adapter*, !dbg !133588
  %4 = getelementptr inbounds i8, i8* %1, i64 4416, !dbg !133589
  %197 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133985
  %151 = getelementptr inbounds i8, i8* %1, i64 556, !dbg !133956
  %105 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133896
  %6 = getelementptr inbounds i8, i8* %1, i64 2264, !dbg !133590
  %29 = getelementptr inbounds i8, i8* %1, i64 4976, !dbg !133656
  %37 = getelementptr inbounds i8, i8* %1, i64 6176, !dbg !133663
  %172 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133971
  %43 = getelementptr inbounds i8, i8* %1, i64 512, !dbg !133663
  %182 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133976
  %18 = getelementptr inbounds i8, i8* %1, i64 544, !dbg !133636
  %48 = getelementptr inbounds i8, i8* %1, i64 544, !dbg !133668
  %89 = getelementptr inbounds i8, i8* %1, i64 8040, !dbg !133858
  %99 = getelementptr inbounds i8, i8* %1, i64 552, !dbg !133892
  %113 = getelementptr inbounds i8, i8* %1, i64 6176, !dbg !133899
  %119 = getelementptr inbounds i8, i8* %1, i64 512, !dbg !133899

while only following inst nodes is connected by PARAMETER_IN edge with root_node due to incorrect traversal and insertion, which will cause data-flow incomplete in latter analysis:

 %205 = getelementptr inbounds i8, i8* %1, i64 5904, !dbg !133988
  %159 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133962
  %141 = getelementptr inbounds i8, i8* %1, i64 544, !dbg !133934
  %193 = getelementptr inbounds i8, i8* %1, i64 6160, !dbg !133982
  %3 = bitcast i8* %1 to %struct.ixgbe_adapter*, !dbg !133588
  %4 = getelementptr inbounds i8, i8* %1, i64 4416, !dbg !133589
  %197 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133985
  %151 = getelementptr inbounds i8, i8* %1, i64 556, !dbg !133956
  %105 = getelementptr inbounds i8, i8* %1, i64 6152, !dbg !133896
  %152 = bitcast i8* %151 to i32*, !dbg !133956
  %160 = bitcast i8* %159 to i32**, !dbg !133962
  %6 = getelementptr inbounds i8, i8* %1, i64 2264, !dbg !133590
  %142 = bitcast i8* %141 to i64*, !dbg !133934
  %9 = bitcast i8* %4 to i8**, !dbg !133603