Made sure all namespace test files get generated.

Also included them in the C++ test.

Change-Id: Ib0c8470f0aacdf16616c27494abdda57a010195d
Tested: on Linux.

tests/namespace_test/NamespaceA/NamespaceB/StructInNestedNS.py

@@ -0,0 +1,23 @@
+# automatically generated, do not modify
+
+# namespace: NamespaceB
+
+import flatbuffers
+
+class StructInNestedNS(object):
+    __slots__ = ['_tab']
+
+    # StructInNestedNS
+    def Init(self, buf, pos):
+        self._tab = flatbuffers.table.Table(buf, pos)
+
+    # StructInNestedNS
+    def A(self): return self._tab.Get(flatbuffers.number_types.Int32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(0))
+    # StructInNestedNS
+    def B(self): return self._tab.Get(flatbuffers.number_types.Int32Flags, self._tab.Pos + flatbuffers.number_types.UOffsetTFlags.py_type(4))
+
+def CreateStructInNestedNS(builder, a, b):
+    builder.Prep(4, 8)
+    builder.PrependInt32(b)
+    builder.PrependInt32(a)
+    return builder.Offset()