Functions: fix multi function test

There were two issues. First, I made a mistake when I switched from unsigned
to signed integers. Second, two classes with the same name were defined in
separate files. Those classes are in an anonymus namespace now, so that they
don't leak into other files.

source/blender/functions/tests/FN_multi_function_network_test.cc

@@ -7,6 +7,7 @@
 #include "FN_multi_function_network_evaluation.hh"
 
 namespace blender::fn::tests {
+namespace {
 
 TEST(multi_function_network, Test1)
 {
@@ -250,4 +251,5 @@ TEST(multi_function_network, Test2)
   }
 }
 
+}  // namespace
 }  // namespace blender::fn::tests

source/blender/functions/tests/FN_multi_function_test.cc

@@ -6,6 +6,7 @@
 #include "FN_multi_function_builder.hh"
 
 namespace blender::fn::tests {
+namespace {
 
 class AddFunction : public MultiFunction {
  public:
@@ -125,7 +126,7 @@ TEST(multi_function, CreateRangeFunction)
 {
   CreateRangeFunction fn;
 
-  GVectorArray ranges(CPPType::get<int32_t>(), 5);
+  GVectorArray ranges(CPPType::get<uint>(), 5);
   GVectorArrayRef<uint> ranges_ref(ranges);
   Array<uint> sizes = {3, 0, 6, 1, 4};
 
@@ -382,4 +383,5 @@ TEST(multi_function, CustomMF_Convert)
   EXPECT_EQ(outputs[2], 9);
 }
 
+}  // namespace
 }  // namespace blender::fn::tests