Fix use after free in CombineTMEMLoadAndStore (#6433)

The patch fixes use-after-free error in the recently introduced
HoistTMEMAlloc.cpp which was detected by the asan build.

We cannot use iterator to the users after erasing the current user of
it.
The solution is to wrap the iterator with make_early_inc_range.

Author: loislo

lib/Dialect/TritonGPU/Transforms/HoistTMEMAlloc.cpp

@@ -128,7 +128,7 @@ class CombineTMEMLoadAndStore : public OpRewritePattern<ttng::TMEMLoadOp> {
   LogicalResult matchAndRewrite(ttng::TMEMLoadOp load,
                                 PatternRewriter &rewriter) const override {
     bool foundStore = false;
-    for (auto user : load->getUsers()) {
+    for (auto user : llvm::make_early_inc_range(load->getUsers())) {
       if (auto store = dyn_cast<ttng::TMEMStoreOp>(user)) {
         if (store.getDst() != load.getSrc()) {
           continue;