Do not allow constants to be bound by lambda expressions

Do not allow constants to be bound by lambda expressions

Functions and macros would signal errors, but lambda expressions
have always been allowed to bind symbols declared to be constant:

(%i1) declare (c, constant)$

(%i2) foo (c) := bar$
define: in definition of foo, found bad argument c
 -- an error. To debug this try: debugmode(true);

(%i3) lambda ([c], c) (baz);
(%o3) baz

The test suite runs fine, with new tests (another test has been
added to rtest_translator).  No changes in the share test suite.