HELLO: Zero HULK BSS region after mapping it

src/hello/hello.d

@@ -419,6 +419,8 @@ private bool map_hulk(PageTable * pt_base)
     {
         return false;
     }
+    /* Zero BSS region. */
+    memset64(cast(void *)bootinfo().bss_phys, 0u, hulk_bss_size() / 8);
     /* Map HULK stack. */
     virt = hulk_virt_stack_top() - hulk_stack_size();
     if (!map4kregion(virt, bootinfo().stack_phys, hulk_stack_size(), pt_base))