Add some logging after download is finished. NFC (#1413)

Also move some code outside of the `using` block.

emsdk.py

@@ -682,7 +682,6 @@ def download_with_curl(url, file_name):
 
 def download_with_urllib(url, file_name):
   u = urlopen(url)
-  with open(file_name, 'wb') as f:
   file_size = get_content_length(u)
   if file_size > 0:
     print("Downloading: %s from %s, %s Bytes" % (file_name, url, file_size))
@@ -696,6 +695,8 @@ def download_with_urllib(url, file_name):
   block_sz = 256 * 1024
   if not TTY_OUTPUT:
       print(' [', end='')
+
+  with open(file_name, 'wb') as f:
     while True:
         buffer = u.read(block_sz)
         if not buffer:
@@ -713,10 +714,13 @@ def download_with_urllib(url, file_name):
                     print('-', end='')
                     sys.stdout.flush()
                     progress_shown += 1
+
   if not TTY_OUTPUT:
     print(']')
     sys.stdout.flush()
 
+  debug_print('finished downloading (%d bytes)' % file_size_dl)
+
 
 # On success, returns the filename on the disk pointing to the destination file that was produced
 # On failure, returns None.