hyper: implement unpausing via client reader

Just a tidy up to contain 'ifdef' pollution of common
code parts with implementation specifics.

- remove the ifdef hyper unpausing in easy.c
- add hyper client reader for CURL_CR_PROTOCOL phase
  that implements the unpause method for calling
  the hyper waker if it is set

Closes #13075

scripts/singleuse.pl

@@ -46,6 +46,7 @@ my %wl = (
     'Curl_xfer_write_resp' => 'internal api',
     'Curl_creader_def_init' => 'internal api',
     'Curl_creader_def_close' => 'internal api',
+    'Curl_creader_def_read' => 'internal api',
     'Curl_creader_def_total_length' => 'internal api',
 );