MC: whitespace, grouping for COFF section setup

Add some whitespace, combine two sequential conditionals into a single one.
Reformat some section definitions to maintain uniformity in the function.
NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210405 91177308-0d34-0410-b5e6-96231b3b80d8
MC: fix ctor/dtor section for windows-itanium

This adjusts the section setup for the windows-itanium environment.  This
environment does not report to be a known windows msvc environment, even though
it is (nearly) identical to the MSVC environment for C code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210406 91177308-0d34-0410-b5e6-96231b3b80d8
MC: make ELF .type handling more GNU AS compatible

GAS documents the .type directive as having an optional comma following the key
symbol name when using the STT_<TYPE_IN_UPPER_CASE> form.  However, it treats
the comma as optional in all cases.  This makes the IAS support both forms of
inputs.  Furthermore, the prefixed forms take either the upper case name or the
lower case alias.

The tests are split into two separate sets as the hash character serves as a
comment character on x86, which is tested in the second set by using arm-elf
which uses the at symbol as a comment character.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210407 91177308-0d34-0410-b5e6-96231b3b80d8