AMDGPU: Remove disable-irstructurizer subtarget feature

The only real reason to use it is for testing, so replace
it with a command line option instead of a potentially function
dependent feature.

llvm-svn: 273653
diff --git a/llvm/test/CodeGen/AMDGPU/structurize.ll b/llvm/test/CodeGen/AMDGPU/structurize.ll
index 02e592e..174e64e 100644
--- a/llvm/test/CodeGen/AMDGPU/structurize.ll
+++ b/llvm/test/CodeGen/AMDGPU/structurize.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -march=r600 -mcpu=redwood -mattr=disable-irstructurizer | FileCheck %s
+; RUN: llc < %s -march=r600 -mcpu=redwood -r600-ir-structurize=0 | FileCheck %s
 ; Test case for a crash in the AMDILCFGStructurizer from a CFG like this:
 ;
 ;                            entry