test: Telex goes in the language table like every other map

The unit suite built a Lang of its own for Telex and loaded telex.map
into it, so the tests that drive the real table had to swap the map in
and out around themselves.  testmapinit loads it where it belongs.

tests/test.h

@@ -1,8 +1,6 @@
 /* Included after dat.h and fn.h (or after the source under test). */
 #include "cutest/cutest.h"
 
-extern Lang testvi;
-
 /*
  * A test's stand-in for imthread: handles engine requests from keyc,
  * tracing each one first.  Requests whose op is holdop (every request