lower L7: remove unused AST.TxtLen and AST.SetKind

Tree-wide scan (including the tests) shows no references.  AST.AddChild
is kept: tests/t_ast.mod uses it.

compiler/src/AST.def

@@ -115,7 +115,6 @@ PROCEDURE AddTxt (s : ARRAY OF CHAR) : TxtIndex;
 PROCEDURE Txt (i : TxtIndex; VAR s : ARRAY OF CHAR);
 (* Copies the i-th text into s (empty when out of range). *)
 
-PROCEDURE TxtLen (i : TxtIndex) : CARDINAL;
 
   (* ---------------- node construction ---------------- *)
 
@@ -135,7 +134,6 @@ PROCEDURE MakeUn (kind, op : INTEGER; e : Node) : Node;
   (* ---------------- node accessors ---------------- *)
 
 PROCEDURE Kind (n : Node) : INTEGER;
-PROCEDURE SetKind (n : Node; kind : INTEGER);
 
 PROCEDURE Op (n : Node) : INTEGER;
 PROCEDURE SetOp (n : Node; op : INTEGER);

compiler/src/AST.mod

@@ -93,12 +93,6 @@ PROCEDURE Txt (i : TxtIndex; VAR s : ARRAY OF CHAR);
     s[k] := CHR(0)
   END Txt;
 
-PROCEDURE TxtLen (i : TxtIndex) : CARDINAL;
-  BEGIN
-    IF (i < 0) OR (i >= VAL(INTEGER, nTxt)) THEN RETURN 0 END;
-    RETURN poolLen[i]
-  END TxtLen;
-
 PROCEDURE InitNode (n : Node);
   VAR j: CARDINAL;
   BEGIN
@@ -168,12 +162,6 @@ PROCEDURE Kind (n : Node) : INTEGER;
     RETURN arena[n].kind
   END Kind;
 
-PROCEDURE SetKind (n : Node; kind : INTEGER);
-  BEGIN
-    IF (n >= 0) AND (n <= VAL(INTEGER, nNodes) - 1) THEN
-      arena[n].kind := kind END
-  END SetKind;
-
 PROCEDURE Op (n : Node) : INTEGER;
   BEGIN
     IF (n < 0) OR (n > VAL(INTEGER, nNodes) - 1) THEN RETURN -1 END;