test: add datum shift related tests for transformations crossing antimeridian

If using the proposed patch in PR #2616 refreshed as,

```
diff --git a/src/4D_api.cpp b/src/4D_api.cpp
index c7725d3a..3bd58a97 100644
--- a/src/4D_api.cpp
+++ b/src/4D_api.cpp
@@ -998,7 +998,7 @@ static void reproject_bbox(PJ* pjGeogToCrs,
         constexpr int XY_SIZE = N_STEPS_P1 * 4;
         std::vector<double> x(XY_SIZE);
         std::vector<double> y(XY_SIZE);
-        const double step_lon = (east_lon - west_lon) / N_STEPS;
+        const double step_lon = (((east_lon >= west_lon) ? east_lon : east_lon + 360) - west_lon) / N_STEPS;
         const double step_lat = (north_lat - south_lat) / N_STEPS;
         for( int j = 0; j <= N_STEPS; j++ )
         {
@@ -1244,7 +1244,7 @@ std::vector<PJCoordOperation> pj_create_prepared_operations(PJ_CONTEXT *ctx,
             {
                 const bool isOffshore =
                     areaName && strstr(areaName, "- offshore");
-                if( west_lon <= east_lon )
+                if( true || west_lon <= east_lon )
                 {
                     op = add_coord_op_to_list(i, op,
                         west_lon, south_lat, east_lon, north_lat,
```

we'd get an incorrect result on one point, using the 'Pulkovo 1942 to WGS 84 (16)' less accurate transformation
due to mis-computation of bounding boxes.
```
--- ../test/cli/tv_out.dist	2021-04-07 22:29:02.706095239 +0200
+++ test/cli/tv_out	2021-04-07 22:29:35.809579495 +0200
@@ -499,7 +499,7 @@
 ##############################################################
 Check that we can use a transformation spanning the antimeridian (should use Pulkovo 1942 to WGS 84 (20))
 50 179.999999999	49d59'59.36"N	179d59'52.133"W 0.000
-50 -179.999999999	49d59'59.36"N	179d59'52.133"W 0.000
+50 -179.999999999	49d59'59.422"N	179d59'52.184"W 0.000
 ##############################################################
 Check that we can use a transformation spanning the antimeridian (should use Pulkovo 1942 to WGS 84 (20))
 5540944.47  499999.999	49d59'59.36"N	179d59'52.133"W 0.000
```

0 files changed, 0 insertions, 0 deletions