Detect when typedefs form a cycle

[litherum]

Migrated from https://bugs.webkit.org/show_bug.cgi?id=186768:

At 2018-06-18T16:01:16Z, rmorisset@apple.com wrote:

typedef a = b;
typedef b = a;

currently hangs the interpreter until it has a stack overflow.
Ideally it should be detected, and give a nicer error message.

[litherum]

At 2018-08-30T00:17:54Z, mmaxfield@apple.com wrote:
Other types too: enums, arrays, structs, etc. (I don't know how they could be circular, but we should prove that it isn't possible using any type)

[litherum]

At 2018-08-30T00:18:02Z, mmaxfield@apple.com wrote:
*** Bug 189024 has been marked as a duplicate of this bug. ***