Blocked module clients should be aware when a key is deleted (#11310)

The use case is a module that wants to implement a blocking command on a key that
necessarily exists and wants to unblock the client in case the key is deleted (much like
what we implemented for XREADGROUP in #10306)

New module API:
* RedisModule_BlockClientOnKeysWithFlags

Flags:
* REDISMODULE_BLOCK_UNBLOCK_NONE
* REDISMODULE_BLOCK_UNBLOCK_DELETED

### Detailed description of code changes

blocked.c:
1. Both module and stream functions are called whether the key exists or not, regardless of
  its type. We do that in order to allow modules/stream to unblock the client in case the key
  is no longer present or has changed type (the behavior for streams didn't change, just code
  that moved into serveClientsBlockedOnStreamKey)
2. Make sure afterCommand is called in serveClientsBlockedOnKeyByModule, in order to propagate
  actions from moduleTryServeClientBlockedOnKey.
3. handleClientsBlockedOnKeys: call propagatePendingCommands directly after lookupKeyReadWithFlags
  to prevent a possible lazy-expire DEL from being mixed with any command propagated by the
  preceding functions.
4. blockForKeys: Caller can specifiy that it wants to be awakened if key is deleted.
   Minor optimizations (use dictAddRaw).
5. signalKeyAsReady became signalKeyAsReadyLogic which can take a boolean in case the key is deleted.
  It will only signal if there's at least one client that awaits key deletion (to save calls to
  handleClientsBlockedOnKeys).
  Minor optimizations (use dictAddRaw)

db.c:
1. scanDatabaseForDeletedStreams is now scanDatabaseForDeletedKeys and will signalKeyAsReady
  for any key that was removed from the database or changed type. It is the responsibility of the code
  in blocked.c to ignore or act on deleted/type-changed keys.
2. Use the new signalDeletedKeyAsReady where needed

blockedonkey.c + tcl:
1. Added test of new capabilities (FSL.BPOPGT now requires the key to exist in order to work)

1 files changed, 12 insertions, 5 deletions

diff --git a/tests/modules/blockonkeys.c b/tests/modules/blockonkeys.c
index 1aa576489..9b6c5e60b 100644
--- a/tests/modules/blockonkeys.c
+++ b/tests/modules/blockonkeys.c
@@ -5,6 +5,8 @@
 #include <assert.h>
 #include <unistd.h>
 
+#define UNUSED(V) ((void) V)
+
 #define LIST_SIZE 1024
 
 typedef struct {
@@ -174,7 +176,7 @@ int bpopgt_reply_callback(RedisModuleCtx *ctx, RedisModuleString **argv, int arg
 
     fsl_t *fsl;
     if (!get_fsl(ctx, keyname, REDISMODULE_READ, 0, &fsl, 0) || !fsl)
-        return REDISMODULE_ERR;
+        return RedisModule_ReplyWithError(ctx,"UNBLOCKED key no longer exists");
 
     if (fsl->list[fsl->length-1] <= *pgt)
         return REDISMODULE_ERR;
@@ -212,12 +214,17 @@ int fsl_bpopgt(RedisModuleCtx *ctx, RedisModuleString **argv, int argc) {
     if (!get_fsl(ctx, argv[1], REDISMODULE_READ, 0, &fsl, 1))
         return REDISMODULE_OK;
 
-    if (!fsl || fsl->list[fsl->length-1] <= gt) {
+    if (!fsl)
+        return RedisModule_ReplyWithError(ctx,"ERR key must exist");
+
+    if (fsl->list[fsl->length-1] <= gt) {
         /* We use malloc so the tests in blockedonkeys.tcl can check for memory leaks */
         long long *pgt = RedisModule_Alloc(sizeof(long long));
         *pgt = gt;
-        RedisModule_BlockClientOnKeys(ctx, bpopgt_reply_callback, bpopgt_timeout_callback,
-                                      bpopgt_free_privdata, timeout, &argv[1], 1, pgt);
+        RedisModule_BlockClientOnKeysWithFlags(
+            ctx, bpopgt_reply_callback, bpopgt_timeout_callback,
+            bpopgt_free_privdata, timeout, &argv[1], 1, pgt,
+            REDISMODULE_BLOCK_UNBLOCK_DELETED);
     } else {
         RedisModule_ReplyWithLongLong(ctx, fsl->list[--fsl->length]);
     }
@@ -469,7 +476,7 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
         .aof_rewrite = fsl_aofrw,
         .mem_usage = NULL,
         .free = fsl_free,
-        .digest = NULL
+        .digest = NULL,
     };
 
     fsltype = RedisModule_CreateDataType(ctx, "fsltype_t", 0, &tm);