tests: Fixes for boxes

cxxrtl `test_unconnected_output` and simple_abc9 `abc9.v` both expect boxed modules in the outputs, so make sure they work as expected.

tests/cxxrtl/run-test.sh

@@ -13,5 +13,5 @@ run_subtest value
 run_subtest value_fuzz
 
 # Compile-only test.
-../../yosys -p "read_verilog test_unconnected_output.v; proc; clean; write_cxxrtl cxxrtl-test-unconnected_output.cc"
+../../yosys -p "read_verilog test_unconnected_output.v; select =*; proc; clean; write_cxxrtl cxxrtl-test-unconnected_output.cc"
 ${CC:-gcc} -std=c++11 -c -o cxxrtl-test-unconnected_output -I../../backends/cxxrtl/runtime cxxrtl-test-unconnected_output.cc

tests/simple_abc9/run-test.sh

@@ -49,6 +49,6 @@ exec ${MAKE:-make} -f ../tools/autotest.mk $seed *.v *.sv EXTRA_FLAGS="-f \"veri
     clean; \
     check -assert * abc9_test037 %d; \
     select -assert-none t:${DOLLAR}_NOT_ t:${DOLLAR}_AND_ %%; \
-    setattr -mod -unset blackbox -unset whitebox'"
+    setattr -mod -unset blackbox -unset whitebox =*'"
 
 # NOTE: Skip 'check -assert' on abc9_test037 because it intentionally has a combinatorial loop