Fixed #36492 -- Restored exact boolean lookup against literals on SQLite.

Performance regression in 37e6c5b on SQLite. Just like MySQL, and presumably
Oracle, which don't have a native boolean type and incidently store booleans in
integer columns, indices on such columns cannot be used when explicit boolean
literal equalities are omitted.

Adapt the logic introduced by refs #32691 for MySQL to be used for all backends
that don't support native boolean fields instead of special casing MySQL,
SQLite, and Oracle in their own special way.

Note that review of this work surfaced that SQLite's query planner also cannot
make use of indices when dealing with expressions of form

   WHERE NOT (indexed_bool_field = false)

but that's a long standing problem unrelated to the restorative work performed
in this patch.

Thanks Klaas van Schelven for the report.

1 files changed, 10 insertions, 5 deletions

diff --git a/django/db/models/lookups.py b/django/db/models/lookups.py
index 4c08999fb6..eef7bc93a5 100644
--- a/django/db/models/lookups.py
+++ b/django/db/models/lookups.py
@@ -151,11 +151,16 @@ class Lookup(Expression):
         # expression unless they're wrapped in a CASE WHEN.
         wrapped = False
         exprs = []
-        for expr in (self.lhs, self.rhs):
-            if connection.ops.conditional_expression_supported_in_where_clause(expr):
-                expr = Case(When(expr, then=True), default=False)
-                wrapped = True
-            exprs.append(expr)
+        if getattr(self.lhs, "conditional", False) and getattr(
+            self.rhs, "conditional", False
+        ):
+            for expr in (self.lhs, self.rhs):
+                if connection.ops.conditional_expression_supported_in_where_clause(
+                    expr
+                ):
+                    expr = Case(When(expr, then=True), default=False)
+                    wrapped = True
+                exprs.append(expr)
         lookup = type(self)(*exprs) if wrapped else self
         return lookup.as_sql(compiler, connection)