Fix shape generation with num-const-inputs-concat option

Change-Id: I2a0aa63a4256629d12166638812dc5b854db2ddf
Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
diff --git a/verif/tosa_test_gen.py b/verif/tosa_test_gen.py
index 07dc7e5..fbf240d 100644
--- a/verif/tosa_test_gen.py
+++ b/verif/tosa_test_gen.py
@@ -404,10 +404,12 @@
     def tgConcatConstInput(testGen, shapeList, axis):
         # Split concat shape along axis to allow for multiple const inputs
         # without making too many large tensors
-        shape = shapeList[0]
-        if len(shapeList) == 2 or shape[axis] < len(shapeList):
+        if len(shapeList) == 2 or shapeList[0][axis] < len(shapeList):
             return shapeList
 
+        # Create copy of shape we are going to split (so we don't alter shapeList)
+        shape = shapeList[0].copy()
+        # Add original shape as first input
         new_shapeList = [shape.copy()]
         length_on_axis = shape[axis]
         remaining_length = length_on_axis