Get the second process elf from a MemoryObject instead of hardcoding.

Allows us to delete the CopyIntoNonResidentProcess function and simply
rely on the MemoryObject copy functions.

sys/test.cpp

@@ -1,11 +1,12 @@
 #include <mammoth/debug.h>
 #include <mammoth/process.h>
-
-constexpr uint64_t prog2 = 0x00000020'00000000;
+#include <zcall.h>
 
 int main() {
   dbgln("Testing");
-  check(SpawnProcessFromElfRegion(prog2));
+  uint64_t vaddr;
+  check(ZAddressSpaceMap(Z_INIT_AS_SELF, 0, Z_INIT_BOOT_VMMO, &vaddr));
+  check(SpawnProcessFromElfRegion(vaddr));
   dbgln("Return");
   return 0;
 }