Set home path, remove path modification that belongs in gz-tools

Signed-off-by: Addisu Z. Taddese <addisu@openrobotics.org>

src/cmd/cmdsdformat.rb.in

@@ -188,8 +188,6 @@ class Cmd
     if defined? RubyInstaller
       # RubyInstaller does not search for dlls in PATH or the directory that tests are running from,
       # so we'll add the parent directory of the plugin to the search path.
-      ENV['RUBY_DLL_PATH'] = ENV['PATH']
-      RubyInstaller::Runtime.enable_dll_search_paths
       # https://github.com/oneclick/rubyinstaller2/wiki/For-gem-developers#-dll-loading
       RubyInstaller::Runtime.add_dll_directory(File.dirname(plugin))
     end

src/gz_TEST.cc

@@ -2094,6 +2094,16 @@ int main(int argc, char **argv)
   gz::utils::setenv("LD_LIBRARY_PATH", testLibraryPath);
 #endif
 
+  // temporarily set HOME
+  std::string homeDir;
+  sdf::testing::TestTmpPath(homeDir);
+
+#ifdef _WIN32
+  gz::utils::setenv("HOMEPATH", homeDir);
+#else
+  gz::utils::setenv("HOME", homeDir);
+#endif
+
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }