Split off sqlite3DbFreeNN() from sqlite3DbFree() and use it in cases where
we know that the argument to be freed is never NULL.

FossilOrigin-Name: ad90e8bb5e47945607c8fb47b6ade8cfc52a9b684805cc40132629be0ecc14cc
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index a0acec4..2b3c934 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3477,6 +3477,7 @@
 void *sqlite3DbReallocOrFree(sqlite3 *, void *, u64);
 void *sqlite3DbRealloc(sqlite3 *, void *, u64);
 void sqlite3DbFree(sqlite3*, void*);
+void sqlite3DbFreeNN(sqlite3*, void*);
 int sqlite3MallocSize(void*);
 int sqlite3DbMallocSize(sqlite3*, void*);
 void *sqlite3ScratchMalloc(int);