TS-2352: refine THREAD_ALLOC feature

1) Move the definition of "ProxyAllocator xxxx" in EThread class to its
   parent Thread class, so that all threads can feel free to use
   THREAD_ALLOC feature.

2) Disable THREAD_ALLOC when enable reclaimable-freelist as reclaimable
   freelist has implemented thread-local pool.

Signed-off-by: Yunkai Zhang <qiushu.zyk@taobao.com>