Enable running SIGSEGV handler on non-alternate stack (#25196)
Enable running SIGSEGV handler on non-alternate stack (#25196)

When a third party library that someone loads into a coreclr process registers
its own SIGSEGV handler and then chain-calls coreclr SIGSEGV handler on a
non-alternate stack, coreclr would currently crash.
This fix enables it to execute the SIGSEGV handler on the non-alternate stack
(original stack of the interrupted thread) in such case.
The disadvantage is that stack overflow would lead to silent crash in such a
case, but we cannot do anything about it.
wtgodbe/coreclr,krk/coreclr,krk/coreclr,poizan42/coreclr,poizan42/coreclr,cshung/coreclr,poizan42/coreclr,wtgodbe/coreclr,cshung/coreclr,wtgodbe/coreclr,wtgodbe/coreclr,wtgodbe/coreclr,poizan42/coreclr,krk/coreclr,krk/coreclr,cshung/coreclr,cshung/coreclr,cshung/coreclr,poizan42/coreclr,krk/coreclr,wtgodbe/coreclr,poizan42/coreclr,krk/coreclr,cshung/coreclr