Fix UAF in ARMConstantIslandPass.

Revoke the change in llvm#146198

Author: qinkunbao

llvm/lib/Target/ARM/ARMConstantIslandPass.cpp

@@ -476,8 +476,8 @@ bool ARMConstantIslands::runOnMachineFunction(MachineFunction &mf) {
 
     LLVM_DEBUG(dbgs() << "Beginning BR iteration #" << NoBRIters << '\n');
     bool BRChange = false;
-    for (ImmBranch &Br : llvm::make_early_inc_range(ImmBranches))
-      BRChange |= fixupImmediateBr(Br);
+    for (unsigned i = 0, e = ImmBranches.size(); i != e; ++i)
+      BRChange |= fixupImmediateBr(ImmBranches[i]);
     if (BRChange && ++NoBRIters > 30)
       report_fatal_error("Branch Fix Up pass failed to converge!");
     LLVM_DEBUG(dumpBBs());