travis.yml: Run tcg tests with tci

travis.yml: Run tcg tests with tci

So far we only have compile coverage for tci. But since commit
2f160e0f9797c7522bfd0d09218d0c9340a5137c ("tci: Add implementation
for INDEX_op_ld16u_i64") has been included now, we can also run the
"tcg" and "qtest" tests with tci, so let's enable them in Travis now.
Since we don't gain much additional test coverage by compiling all
targets, and TCI is broken e.g. with the Sparc targets, we also limit
the target list to a reasonable subset now (which should still get us
test coverage by tests/boot-serial-test for example).

Tested-by: Stefan Weil <sw@weilnetz.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20191204083133.6198-1-thuth@redhat.com>
[AJB: just --enable-debug-tcg]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>