MC: Emit COFF section flags in the "proper" order

COFF section flags are not idempotent:
  'rd' will make a read-write section because 'd' implies write
  'dr' will make a read-only section because 'r' disables write

llvm-svn: 228490
diff --git a/llvm/test/CodeGen/X86/coff-comdat.ll b/llvm/test/CodeGen/X86/coff-comdat.ll
index dcbbe10..44e1cb2 100644
--- a/llvm/test/CodeGen/X86/coff-comdat.ll
+++ b/llvm/test/CodeGen/X86/coff-comdat.ll
@@ -73,20 +73,20 @@
 ; CHECK: .globl  @v8@0
 ; CHECK: .section        .text,"xr",discard,@f8@0
 ; CHECK: .globl  @f8@0
-; CHECK: .section        .bss,"wb",associative,_f1
+; CHECK: .section        .bss,"bw",associative,_f1
 ; CHECK: .globl  _v1
-; CHECK: .section        .bss,"wb",associative,_f2
+; CHECK: .section        .bss,"bw",associative,_f2
 ; CHECK: .globl  _v2
-; CHECK: .section        .bss,"wb",associative,_f3
+; CHECK: .section        .bss,"bw",associative,_f3
 ; CHECK: .globl  _v3
-; CHECK: .section        .bss,"wb",associative,_f4
+; CHECK: .section        .bss,"bw",associative,_f4
 ; CHECK: .globl  _v4
-; CHECK: .section        .bss,"wb",associative,_f5
+; CHECK: .section        .bss,"bw",associative,_f5
 ; CHECK: .globl  _v5
-; CHECK: .section        .bss,"wb",associative,_f6
+; CHECK: .section        .bss,"bw",associative,_f6
 ; CHECK: .globl  _v6
-; CHECK: .section        .bss,"wb",same_size,_f6
+; CHECK: .section        .bss,"bw",same_size,_f6
 ; CHECK: .globl  _f6
-; CHECK: .section        .rdata,"rd",largest,_vftable
+; CHECK: .section        .rdata,"dr",largest,_vftable
 ; CHECK: .globl  _vftable
 ; CHECK: _vftable = L_some_name+4