Revert "Fix allocations of SmallVector and SmallPtrSet so they are more prone to"

This reverts commit 617330909f0c26a3f2ab8601a029b9bdca48aa61.

It broke the bots:

/home/clangbuild2/clang-ppc64-2/llvm.src/unittests/ADT/SmallVectorTest.cpp:150: PushPopTest
/home/clangbuild2/clang-ppc64-2/llvm.src/unittests/ADT/SmallVectorTest.cpp:118: Failure
Value of: v[i].getValue()
  Actual: 0
Expected: value
Which is: 2