[ELF] Delete redundant pageAlign at PT_GNU_RELRO boundaries after D58892

Summary:
After D58892 split the RW PT_LOAD on the PT_GNU_RELRO boundary, the new
layout is:

PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro)) PT_LOAD(.data. .bss)

The two pageAlign() calls at PT_GNU_RELRO boundaries are redundant due
to the existence of PT_LOAD.

Reviewers: grimar, peter.smith, ruiu, espindola

Reviewed By: ruiu

Subscribers: sfertile, atanasyan, emaste, arichardson, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64854

llvm-svn: 366307