Fix bidirectional sequence RNN crash when auxiliary input is omitted

The crash would happen if auxiliary inputs were provided with a shape
with less than 3 dimensions. This is the case when marking optional
input as omitted.

The tests weren't catching this behaviour because they set three- or
two-dimensional shape consisting of zeros instead of just
one-dimensional zero. The change modifies the tests so that they use
one-dimensional shape.

Fix: 135242001
Test: NeuralNetworksTest_static
Change-Id: I47168d6a59445d2591a3c25ce7bbd4e17e6b2547
Merged-In: I47168d6a59445d2591a3c25ce7bbd4e17e6b2547
(cherry picked from commit 66ac07117146b77d9be8e72c6e615dea1adc9a64)

common/operations/BidirectionalSequenceRNN.cpp

diff --git a/common/operations/BidirectionalSequenceRNN.cpp b/common/operations/BidirectionalSequenceRNN.cpp
index 0e8bc6d..32ab00f 100644
--- a/common/operations/BidirectionalSequenceRNN.cpp
+++ b/common/operations/BidirectionalSequenceRNN.cpp
@@ -168,12 +168,18 @@
     const uint32_t maxTime = getSizeOfDimension(inputShape, 0);
     const uint32_t batchSize = getSizeOfDimension(inputShape, 1);
     const uint32_t inputSize = getSizeOfDimension(inputShape, 2);
-    const uint32_t auxInputSize = getSizeOfDimension(auxInputShape, 2);
+    uint32_t auxInputSize = 0;
+    if (hasAuxInputs) {
+        auxInputSize = getSizeOfDimension(auxInputShape, 2);
+    }
     const uint32_t fwNumUnits = getSizeOfDimension(fwWeightsShape, 0);
     const uint32_t bwNumUnits = getSizeOfDimension(bwWeightsShape, 0);
 
     Shape fixedTimeInputShape = removeFirstDim(inputShape);
-    Shape fixedTimeAuxInputShape = removeFirstDim(auxInputShape);
+    Shape fixedTimeAuxInputShape = auxInputShape;
+    if (hasAuxInputs) {
+        fixedTimeAuxInputShape = removeFirstDim(auxInputShape);
+    }
 
     // Create an additional buffer to store a hidden state between steps.
     std::vector<T> tempHiddenState(batchSize * fwNumUnits);