Update tensorflow submodule for tflite_benchmark_model (#2212)

tflite_benchmark_model in v1.9.0 does not build nor work.
This patch fixes build failure with two cherry-picked patches.

Signed-off-by: Sanggyu Lee <sg5.lee@samsung.com>

diff --git a/externals/tensorflow b/externals/tensorflow
index fd70f51..d454420 160000 (submodule)
--- a/externals/tensorflow
+++ b/externals/tensorflow
@@ -1 +1 @@
-Subproject commit fd70f515599ee5d357e9beda63a5b161abaf12b1
+Subproject commit d4544206d615028775aa47ef338b610de94d04dc