Extend IREE_COMMON_INCLUDE_DIRS for external dialects (#2855)

Required to bump the IREE submodule used in
https://github.com/iml130/iree-template-cpp. TensorFlow is otherwise
unable to find tablegenerated files.
diff --git a/build_tools/cmake/iree_copts.cmake b/build_tools/cmake/iree_copts.cmake
index 7563c1f..8ac8c2d 100644
--- a/build_tools/cmake/iree_copts.cmake
+++ b/build_tools/cmake/iree_copts.cmake
@@ -249,6 +249,8 @@
   ${PROJECT_SOURCE_DIR}/third_party/tensorflow/tensorflow/compiler/mlir/hlo/include/
   ${PROJECT_BINARY_DIR}/build_tools/third_party/tensorflow
   ${PROJECT_BINARY_DIR}/build_tools/third_party/tensorflow/tensorflow/compiler/mlir/hlo/include/
+  ${PROJECT_BINARY_DIR}/build_tools/third_party/tensorflow/tensorflow/compiler/mlir/hlo/lib/Dialect/mhlo/IR/
+  ${PROJECT_BINARY_DIR}/build_tools/third_party/tensorflow/tensorflow/compiler/mlir/hlo/lib/Dialect/mhlo/transforms
 )
 
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