[MIR] Allow frame-setup and frame-destroy on the same instruction

Nothing prevents us from having both frame-setup and frame-destroy on
the same instruction.

When merging:
* frame-setup OPCODE1
* frame-destroy OPCODE2
into
* frame-setup frame-destroy OPCODE3

we want to be able to print and parse both flags.

llvm-svn: 327442
diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 7d04e6b..5f3989b 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -1292,7 +1292,7 @@
 
   if (getFlag(MachineInstr::FrameSetup))
     OS << "frame-setup ";
-  else if (getFlag(MachineInstr::FrameDestroy))
+  if (getFlag(MachineInstr::FrameDestroy))
     OS << "frame-destroy ";
 
   // Print the opcode name.