Integrate LLVM at llvm/llvm-project@435225c (#345)

Updates LLVM usage to match llvm/llvm-project@435225c.
Further updates the MLIR-HLO submodule to tensorflow/mlir-hlo@9fefc2b.
diff --git a/build_tools/llvm_version.txt b/build_tools/llvm_version.txt
index 095d00e..f99d29b 100644
--- a/build_tools/llvm_version.txt
+++ b/build_tools/llvm_version.txt
@@ -1 +1 @@
-8bd65e535fb33bc48805bafed8217b16a853e158
+435225c6e2f860ecc53fcd65e193f832569d090e
diff --git a/lib/Conversion/MhloToEmitC/MHLORegionOpsToEmitC.cpp b/lib/Conversion/MhloToEmitC/MHLORegionOpsToEmitC.cpp
index 8265680..8022be5 100644
--- a/lib/Conversion/MhloToEmitC/MHLORegionOpsToEmitC.cpp
+++ b/lib/Conversion/MhloToEmitC/MHLORegionOpsToEmitC.cpp
@@ -14,8 +14,8 @@
 #include "mhlo/IR/hlo_ops.h"
 #include "mlir/Dialect/EmitC/IR/EmitC.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"
-#include "mlir/IR/BlockAndValueMapping.h"
 #include "mlir/IR/BuiltinOps.h"
+#include "mlir/IR/IRMapping.h"
 #include "mlir/Pass/Pass.h"
 
 #include "../PassDetail.h"
@@ -140,8 +140,8 @@
 
     Region &outlinedRegion = outlinedFunc.getRegion();
 
-    BlockAndValueMapping map;
-    region.cloneInto(&outlinedRegion, map);
+    IRMapping mapper;
+    region.cloneInto(&outlinedRegion, mapper);
 
     outlinedFunc.walk([](mhlo::ReturnOp returnOp) {
       OpBuilder replacer(returnOp);
diff --git a/third_party/mlir-hlo b/third_party/mlir-hlo
index 78c6dcf..9fefc2b 160000
--- a/third_party/mlir-hlo
+++ b/third_party/mlir-hlo
@@ -1 +1 @@
-Subproject commit 78c6dcf7d00b5598e211fc22c686ec9ab77abc45
+Subproject commit 9fefc2b333ca7ba195942ca3e7204d7cc5439bfc