ARM: locate user-defined text sections next to default text.

ARM: locate user-defined text sections next to default text.

Make sure functions located in user specified text sections (via the
section attribute) are located together with the default text sections.
Otherwise, for large object files, the relocations for call instructions
are more likely to be out of range. This becomes even more likely in the
presence of LTO.

rdar://12402636

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165254 91177308-0d34-0410-b5e6-96231b3b80d8