Fix a segfault in fts3 that may occur if the snippet, offsets or matchinfo functions are used in a query that does not contain a MATCH clause.

FossilOrigin-Name: 14ab536a96f81595ab8c3dcd4b72075f1a827c8b
diff --git a/test/fts3snippet.test b/test/fts3snippet.test
index d112c5e..614691a 100644
--- a/test/fts3snippet.test
+++ b/test/fts3snippet.test
@@ -432,7 +432,34 @@
     {2 2 1 3 3 3 6 3 0 0 0 2 3 2}          
     {2 2 1 3 3 3 6 3 0 0 0 2 3 2}
   }]
+
+  # EVIDENCE-OF: R-56101-59725 If used within a SELECT that uses the
+  # "query by rowid" or "linear scan" strategies, then the snippet and
+  # offsets both return an an empty string, and the matchinfo function
+  # returns a blob value zero bytes in size.
+  #
+  set r 1000000                   ;# A rowid that exists in table ft
+  do_select_test $T.10.0 { SELECT rowid FROM ft WHERE rowid = $r } $r
+  do_select_test $T.10.1 {
+    SELECT length(offsets(ft)), typeof(offsets(ft)) FROM ft;
+  } {0 text 0 text 0 text}
+  do_select_test $T.10.2 {
+    SELECT length(offsets(ft)), typeof(offsets(ft)) FROM ft WHERE rowid = $r
+  } {0 text}
+  do_select_test $T.10.3 {
+    SELECT length(snippet(ft)), typeof(snippet(ft)) FROM ft;
+  } {0 text 0 text 0 text}
+  do_select_test $T.10.4 {
+    SELECT length(snippet(ft)), typeof(snippet(ft)) FROM ft WHERE rowid = $r;
+  } {0 text}
+  do_select_test $T.10.5 {
+    SELECT length(matchinfo(ft)), typeof(matchinfo(ft)) FROM ft;
+  } {0 blob 0 blob 0 blob}
+  do_select_test $T.10.6 {
+    SELECT length(matchinfo(ft)), typeof(matchinfo(ft)) FROM ft WHERE rowid = $r
+  } {0 blob}
 }
 
+
 set sqlite_fts3_enable_parentheses 0
 finish_test