optimize(remove) usage of client's pending_querybuf (#10413)

To remove `pending_querybuf`, the key point is reusing `querybuf`, it means master client's `querybuf` is not only used to parse command, but also proxy to sub-replicas.

1. add a new variable `repl_applied` for master client to record how many data applied (propagated via `replicationFeedStreamFromMasterStream()`) but not trimmed in `querybuf`.

2. don't sdsrange `querybuf` in `commandProcessed()`, we trim it to `repl_applied` after the whole replication pipeline processed to avoid fragmented `sdsrange`. And here are some scenarios we cannot trim to `qb_pos`:
    * we don't receive complete command from master
    * master client blocked because of client pause
    * IO threads operate read, master client flagged with CLIENT_PENDING_COMMAND

    In these scenarios, `qb_pos` points to the part of the current command or the beginning of next command, and the current command is not applied yet, so the `repl_applied` is not equal to `qb_pos`.

Some other notes:
* Do not do big arg optimization on master client, since we can only sdsrange `querybuf` after data sent to replicas.
* Set `qb_pos` and `repl_applied` to 0 when `freeClient` in `replicationCacheMaster`.
* Rewrite `processPendingCommandsAndResetClient` to `processPendingCommandAndInputBuffer`, let `processInputBuffer` to be called successively after `processCommandAndResetClient`.

1 files changed, 2 insertions, 2 deletions

diff --git a/tests/support/util.tcl b/tests/support/util.tcl
index 46c9654c8..4ad96ab10 100644
--- a/tests/support/util.tcl
+++ b/tests/support/util.tcl
@@ -122,7 +122,7 @@ proc wait_replica_online r {
     wait_for_condition 50 100 {
         [string match "*slave0:*,state=online*" [$r info replication]]
     } else {
-        fail "replica didn't sync in time"
+        fail "replica didn't online in time"
     }
 }
 
@@ -130,7 +130,7 @@ proc wait_for_ofs_sync {r1 r2} {
     wait_for_condition 50 100 {
         [status $r1 master_repl_offset] eq [status $r2 master_repl_offset]
     } else {
-        fail "replica didn't sync in time"
+        fail "replica offset didn't match in time"
     }
 }