add test for Input example

tests/examples/input/definition.json

+{
+	"executable": [
+		"examples",
+		"ae108-examples-Input"
+	],
+	"compare_stdout": "numeric",
+	"mpi_processes": [
+		1
+	]
+}
\ No newline at end of file

tests/examples/input/references/stdout.txt

+Vec Object: vertex_index_data 1 MPI processes
+  type: seq
+0.
+1.
+2.
+3.
+4.
+5.
+Vec Object: vertex_index_data 1 MPI processes
+  type: seq
+0.
+1.
+2.
+3.
+4.
+5.