[jemalloc] set correct excess in realloc_excess

Author: gnzlbg

src/liballoc_jemalloc/lib.rs

@@ -228,7 +228,7 @@ mod contents {
         }
 
         let flags = align_to_flags(new_align);
-        let ptr = rallocx(ptr as *mut c_void, new_size, flags) as usize;
+        let ptr = rallocx(ptr as *mut c_void, new_size, flags) as *mut u8;
         let alloc_size = sallocx(ptr as *mut c_void, flags);
         if ptr.is_null() {
             let layout = Layout::from_size_align_unchecked(new_size, new_align);