Use `Inst_eddies_loop` from `$PWD`

Since `Inst_eddies_loop` is in the same series of tests as
`Nearby_extr`, take it from `$PWD` rather than `$tests_old_dir`.

Inst_eddies/Tests/short_tests.json

@@ -317,7 +317,7 @@
         "command":
 	[
 	  "$build_dir/Inst_eddies/test_nearby_extr",
-	  "$tests_old_dir/Inst_eddies_loop/SHPC_cyclo_all_dates"
+	  "$PWD/Inst_eddies_loop/SHPC_cyclo_all_dates"
 	]
     },
     {