Force signapk.jar generated in out/host/soong

Before signapk.jar generated, the apexer_test_host_tools cmd script is
run. The cmd script would report signapk is not found in the entire
both of out/host and out/soong/host.

The workaround solution is to force signapk.jar generated in
out/soong/host. To include the java_binary_host module that has the
relationship with signapk make signapk generated in out/soong/host.

Test: # do several time.
    for i in `seq 1 10` ; \
    do\
        make clean; \
        make -j64 apexer_test_host_tools; \
    done
Bug: 160632228
Change-Id: I232d9eeeba28289834760b490eebfcf73eca29e2
1 file changed