[X86] Move AVX512VPOPCNTDQ in __builtin_cpu_support's enum to match trunk gcc.
[X86] Move AVX512VPOPCNTDQ in __builtin_cpu_support's enum to match trunk gcc.

There are two other features before it that we don't currently support in the the frontend or backend so I left placeholders to keep the encoding correct.

I think the compiler-rt implementation of this feature is even further out of date.

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@307456 91177308-0d34-0410-b5e6-96231b3b80d8

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