PROJ_TESTS CMake option in the Superbuild

Analysis

By default the PROJ CMake configure has the PROJ_TESTS option enabled, building PROJ tests. If tests are enabled PROJ will try to download google-test (https://github.com/google/googletest/archive/release-1.8.1.zip) in its configure step. In an offline environment this will result in an error (google-test is not a part of the Superbuild-archive).

Building tests for PROJ is not necessary (even when building otb tests), in the Superbuild we should disable this option.

step to reproduce

In an offline environment, with the superbuild archive:

tar -xvf SuperBuild-archives-7.2.tar.bz2 -C archive_7.2
mkdir sb && cd sb
cmake ../otb/SuperBuild/ -DDOWNLOAD_LOCATION=../archive_7.2
make PROJ 

will result in a download error in PROJ configure step.

Notes

The Superbuild uses PROJ 6.2.1. Starting with PROJ 7.0, the PROJ_TESTS option has been renamed into BUILD_TESTING