[AIX][XCOFF][BUG-Fixed] need to switch back to text section after emit a dumy eh structure

Summary:

in the patch https://reviews.llvm.org/D103651 [AIX][XCOFF] generate eh_info when vector registers are saved according to the traceback table.

when generate eh_info, it switch to other section, when it done, it need to switch back to text section again.

Reviewers: Jason Liu
Differential Revision: https://reviews.llvm.org/105195