Move ARM specific test to ELF/ARM dir

Moving ARM specific test clang-section.s
from MC/ELF to MC/ELF/ARM
Buildbots reported failures on
commit  https://reviews.llvm.org/rL304705
Full details are available at:
 http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/10333

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304706 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/MC/ELF/clang-section.s b/test/MC/ELF/ARM/clang-section.s
similarity index 100%
rename from test/MC/ELF/clang-section.s
rename to test/MC/ELF/ARM/clang-section.s