Skip tests that needs an active internet connection

--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -57,9 +57,4 @@ IF (MSVC_IDE)
 	SET_SOURCE_FILES_PROPERTIES("precompiled.c" COMPILE_FLAGS "/Ycprecompiled.h")
 ENDIF ()
 
-ADD_TEST(offline   "${libgit2_BINARY_DIR}/libgit2_clar" -v -xonline)
 ADD_TEST(invasive  "${libgit2_BINARY_DIR}/libgit2_clar" -v -score::ftruncate -sfilter::stream::bigfile -sodb::largefiles -siterator::workdir::filesystem_gunk -srepo::init -srepo::init::at_filesystem_root)
-ADD_TEST(online    "${libgit2_BINARY_DIR}/libgit2_clar" -v -sonline)
-ADD_TEST(gitdaemon "${libgit2_BINARY_DIR}/libgit2_clar" -v -sonline::push)
-ADD_TEST(ssh       "${libgit2_BINARY_DIR}/libgit2_clar" -v -sonline::push -sonline::clone::ssh_cert -sonline::clone::ssh_with_paths)
-ADD_TEST(proxy     "${libgit2_BINARY_DIR}/libgit2_clar" -v -sonline::clone::proxy_credentials_in_url -sonline::clone::proxy_credentials_request)