Enlarge stack overflow handling stack (#114956)

This is an attempt to fix rare failures in the stack overflow tests that
I was unable to repro locally. The logs I've added so far seems to indicate
that the thread handling the exception crashes with another stack overflow
at the point when it waits for a secondary thread to finish dumping stack
trace.

Author: janvorli

src/coreclr/pal/src/exception/signal.cpp

@@ -206,7 +206,7 @@ BOOL SEHInitializeSignals(CorUnix::CPalThread *pthrCurrent, DWORD flags)
         }
 
         // Allocate the minimal stack necessary for handling stack overflow
-        int stackOverflowStackSize = ALIGN_UP(sizeof(SignalHandlerWorkerReturnPoint), 16) + 8 * 4096;
+        int stackOverflowStackSize = ALIGN_UP(sizeof(SignalHandlerWorkerReturnPoint), 16) + 9 * 4096;
         // Align the size to virtual page size and add one virtual page as a stack guard
         stackOverflowStackSize = ALIGN_UP(stackOverflowStackSize, GetVirtualPageSize()) + GetVirtualPageSize();
         int flags = MAP_ANONYMOUS | MAP_PRIVATE;