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
    Refactor build functions so we can build just HotSpot without any attempt at installation.
    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
    Add backport of JDK-8257794 to fix bogus assert on slowdebug x86-32 Zero builds