.travis.yml: add check-tcg test

Signed-off-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Tested-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>

.travis.yml

@@ -153,3 +153,11 @@ matrix:
         - TEST_CMD=""
       before_script:
         - ./configure ${CONFIG} --extra-cflags="-g3 -O0 -fsanitize=thread -fuse-ld=gold" || { cat config.log && exit 1; }
+    - env:
+        - CONFIG="--disable-system --disable-docs"
+        - TEST_CMD="make check-tcg"
+      script:
+        - make ${MAKEFLAGS} && ${TEST_CMD} ${MAKEFLAGS}
+      sudo: required
+      dist: trusty
+      compiler: gcc