.build,cmd: add -race to test programs

It's not possible to set GOFLAGS=-race because some programs are
built for webassembly where -race is not supported.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

.builds/linux.yml

@@ -28,11 +28,11 @@ tasks:
      sudo apt install -y google-chrome-stable
  - test_gio: |
      cd gio
-     go test ./...
+     go test -race ./...
      GOOS=windows go test -exec=wine ./...
  - test_example: |
      cd gio/example
-     go test ./...
+     go test -race ./...
  - test_cmd: |
      cd gio/cmd
      go test ./...