Extra backwards-compatibility tests verify that UNIQUE and PRIMARY KEY

indices are created in the correct order.  Other backwards-compatibility
tests already cover this, but it does not hurt to double up.

FossilOrigin-Name: 5ca0ea2e9b40a7fa133d2af8a2ecc676de7a8723

test/backcompat.test

@@ -200,6 +200,39 @@ do_allbackcompat_test {
 
   do_test backcompat-1.2.7 { sql1 { PRAGMA integrity_check } } {ok}
   do_test backcompat-1.2.8 { sql2 { PRAGMA integrity_check } } {ok}
+
+  do_test backcompat-2.1 {
+    sql1 {
+      CREATE TABLE t2(a UNIQUE, b PRIMARY KEY, c UNIQUE);
+      INSERT INTO t2 VALUES(1,9,5),(5,5,1),(9,1,9);
+      SELECT * FROM t2 ORDER BY a;
+    }
+  } {1 9 5 5 5 1 9 1 9}
+  do_test backcompat-2.2 {
+    sql2 {
+      SELECT * FROM t2 ORDER BY a;
+    }
+  } {1 9 5 5 5 1 9 1 9}
+  do_test backcompat-2.3 {
+    sql1 {
+      SELECT * FROM t2 ORDER BY b;
+    }
+  } {9 1 9 5 5 1 1 9 5}
+  do_test backcompat-2.4 {
+    sql2 {
+      SELECT * FROM t2 ORDER BY b;
+    }
+  } {9 1 9 5 5 1 1 9 5}
+  do_test backcompat-2.5 {
+    sql1 {
+      SELECT * FROM t2 ORDER BY c;
+    }
+  } {5 5 1 1 9 5 9 1 9}
+  do_test backcompat-2.6 {
+    sql2 {
+      SELECT * FROM t2 ORDER BY c;
+    }
+  } {5 5 1 1 9 5 9 1 9}
 }
 foreach k [lsort [array names ::incompatible]] {
   puts "ERROR: Detected journal incompatibility with version $k"