.travis.yml: drop the travis_retry from tests

This was a crutch when we introduced it - however it does have the
disadvantage of causing tests to timeout with large amounts of logs.
Lets drop it and see if the stability has improved since.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200203090932.19147-16-alex.bennee@linaro.org>

.travis.yml

@@ -103,7 +103,12 @@ script:
     else
         $(exit $BUILD_RC);
     fi
-  - if [ "$BUILD_RC" -eq 0 ] ; then travis_retry ${TEST_CMD} ; else $(exit $BUILD_RC); fi
+  - |
+    if [ "$BUILD_RC" -eq 0 ] ; then
+        ${TEST_CMD} ;
+    else
+        $(exit $BUILD_RC);
+    fi
 after_script:
   - if command -v ccache ; then ccache --show-stats ; fi