gh-112808: Fix mimalloc build on Solaris (#112809)

Author: kulikjak

Objects/mimalloc/prim/unix/prim.c

@@ -310,7 +310,7 @@ static void* unix_mmap(void* addr, size_t size, size_t try_alignment, int protec
       #elif defined(__sun)
       if (allow_large && _mi_os_use_large_page(size, try_alignment)) {
         struct memcntl_mha cmd = {0};
-        cmd.mha_pagesize = large_os_page_size;
+        cmd.mha_pagesize = 2*MI_MiB;
         cmd.mha_cmd = MHA_MAPSIZE_VA;
         if (memcntl((caddr_t)p, size, MC_HAT_ADVISE, (caddr_t)&cmd, 0, 0) == 0) {
           *is_large = true;