Add TODO interop test case for CONTINUATIONS; clean up TODOs

doc/interop-test-descriptions.md

@@ -558,20 +558,14 @@ pushback (i.e., attempts to send succeed only after appropriate delays).
 
 Propagation of status code and message (yangg)
 
-Cancel after sent headers (ctiller - done)
-
-Cancel after received first message (ctiller - done)
-
-Zero-message streams (ejona)
-
-Multiple thousand simultaneous calls on same Channel (ctiller - done)
+Multiple thousand simultaneous calls on same Channel (ctiller)
 
 OAuth2 tokens + Service Credentials from GCE metadata server (GCE->prod only)
 (abhishek)
 
 OAuth2 tokens + JWT signing key (GCE->prod only) (abhishek)
 
-Metadata: client headers, server headers + trailers, binary+ascii (chenw)
+Metadata: client headers, server headers + trailers, binary+ascii
 
 #### Normal priority:
 
@@ -600,6 +594,8 @@ Multiple thousand simultaneous calls on different Channels (ctiller)
 
 Failed TLS hostname verification (ejona?)
 
+Large amount of headers to cause CONTINUATIONs; 63K of 'X's, all in one header.
+
 #### To priorize:
 
 Start streaming RPC but don't send any requests, server responds