Using crtp to refactor the xcoff section header

SUMMARY:
According to https://reviews.llvm.org/D68575#inline-617586, Create a NFC patch for it.

Using crtp to refactor the xcoff section header
Move the define of SectionFlagsReservedMask and SectionFlagsTypeMask from XCOFFDumper.cpp to XCOFFObjectFile.h

Reviewers: hubert.reinterpretcast,jasonliu
Subscribers: rupprecht, seiyai,hiraditya

Differential Revision: https://reviews.llvm.org/D69131