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
