Remove "manual" tags from java coverage integration tests.
Remove "manual" tags from java coverage integration tests.

These were added during https://github.com/bazelbuild/bazel/issues/12696.

The integration tests in question depend on the pre-built version of
java_tools and so would have started to fail when the tests were updated
for the new functionality added.

Now java_tools has been updated (several times), it is safe to allow
automated running of them once again.

Closes #15100.

PiperOrigin-RevId: 436702004

bazelbuild/bazel,cushon/bazel,cushon/bazel,cushon/bazel,bazelbuild/bazel,bazelbuild/bazel,katre/bazel,cushon/bazel,bazelbuild/bazel,bazelbuild/bazel,cushon/bazel,katre/bazel,bazelbuild/bazel,katre/bazel,katre/bazel,cushon/bazel,katre/bazel,katre/bazel