Temporarily move x86 to use Zero in order to get a working build
    
    Replace -mstackrealign with -mincoming-stack-boundary=2 -mpreferred-stack-boundary=4 on x86_32 for stack alignment
    Support a HotSpot-only build so a freshly built libjvm.so can then be used in the bootstrap JDK.
    Explicitly list JIT architectures rather than relying on those with slowdebug builds
    Disable the serviceability agent on Zero architectures even when the architecture itself is supported