delta-find: remove dead code intended to deal with forced delta reuse

Since the case was dealt with sooner (see XXX), we no longer need to deal with
it in this part of the code.

mercurial/revlogutils/deltas.py

@@ -585,12 +585,14 b' def is_good_delta_info(revlog, deltainfo'
     if deltainfo is None:
         return False
 
-    if (
-        revinfo.cachedelta is not None
-        and deltainfo.base == revinfo.cachedelta[0]
-        and revinfo.cachedelta[2] == DELTA_BASE_REUSE_FORCE
-    ):
-        return True
+    # the DELTA_BASE_REUSE_FORCE case should have been taken care of sooner so
+    # we should never end up asking such question. Adding the assert as a
+    # safe-guard to detect anything that would be fishy in this regard.
+    assert (
+        revinfo.cachedelta is None
+        or revinfo.cachedelta[2] != DELTA_BASE_REUSE_FORCE
+        or not revlog._generaldelta
+    )
 
     # - 'deltainfo.distance' is the distance from the base revision --
     #   bounding it limits the amount of I/O we need to do.
@@ -693,14 +695,14 b' def _candidategroups('
         yield None
         return
 
-    if (
-        cachedelta is not None
-        and nullrev == cachedelta[0]
-        and cachedelta[2] == DELTA_BASE_REUSE_FORCE
-    ):
-        # instruction are to forcibly do a full snapshot
-        yield None
-        return
+    # the DELTA_BASE_REUSE_FORCE case should have been taken care of sooner so
+    # we should never end up asking such question. Adding the assert as a
+    # safe-guard to detect anything that would be fishy in this regard.
+    assert (
+        cachedelta is None
+        or cachedelta[2] != DELTA_BASE_REUSE_FORCE
+        or not revlog._generaldelta
+    )
 
     deltalength = revlog.length
     deltaparent = revlog.deltaparent
@@ -736,15 +738,6 b' def _candidategroups('
             if rev in tested:
                 continue
 
-            if (
-                cachedelta is not None
-                and rev == cachedelta[0]
-                and cachedelta[2] == DELTA_BASE_REUSE_FORCE
-            ):
-                # instructions are to forcibly consider/use this delta base
-                group.append(rev)
-                continue
-
             # an higher authority deamed the base unworthy (e.g. censored)
             if excluded_bases is not None and rev in excluded_bases:
                 tested.add(rev)