[ARM] Register ConstantIslands with the pass manager

This allows us to use -stop-before/-stop-after/-run-pass - we can now write
.mir tests.

llvm-svn: 294948
diff --git a/llvm/lib/Target/ARM/ARM.h b/llvm/lib/Target/ARM/ARM.h
index 76227bc..39f7988 100644
--- a/llvm/lib/Target/ARM/ARM.h
+++ b/llvm/lib/Target/ARM/ARM.h
@@ -53,6 +53,7 @@
 
 void initializeARMLoadStoreOptPass(PassRegistry &);
 void initializeARMPreAllocLoadStoreOptPass(PassRegistry &);
+void initializeARMConstantIslandsPass(PassRegistry &);
 
 } // end namespace llvm