[ADT] Fix a bug in DenseSet's initializer_list constructor.

Without this fix, DenseSet crashes with an assertion if constructed with an
initializer_list whose length is not a power of two.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344542 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed