jiri-test: re-enable reader tests
jiri-test: re-enable reader tests

The reader will continue development as a Flutter application and will need
tests/CI again. CL#21912 has modified the reader test task to only run Flutter
tests.

See: https://vanadium-review.googlesource.com/#/c/21912/
Change-Id: Ifd4c951710418606365581370ecf83180498804a

vanadium/go.devtools,vanadium/go.devtools,vanadium/go.devtools