Reapply "rpc_binder: Change `trusty_tipc_fuzzer` to support multiple connections and messages"

This reverts commit b1105589.

This redoes change I9692e4d0295052a8da2204f63be9e52939e70ac3,
fixing the crash and simplifying the logic so it's
more obvious something similar won't happen again.

Bug: 380142627
Bug: 319144781
Test: build.py qemu-generic-arm64-fuzz-test-debug &&
    ./build-root/build-qemu-generic-arm64-fuzz-test-debug/run.py &&
    lunch aosp_lynx-trunk_staging-userdebug &&
    m trusty_binder_rpc_fuzzer_multi_connection &&
    adb root &&
    adb sync data &&
    adb shell /data/fuzz/arm64/trusty_binder_rpc_fuzzer_multi_connection/trusty_binder_rpc_fuzzer_multi_connection -seed=1727807641/data/fuzz/arm64/trusty_binder_rpc_fuzzer_multi_connection/input
Change-Id: I049e94c87083a4e212aaf7edb1eca421dc1e76ed