Proxy Constant Subroutines are in, so are an enhancement to note, even

Proxy Constant Subroutines are in, so are an enhancement to note, even
though they are disabled by default.
Clean up "new tests":
* add descriptions of all the new test files in t
  (and wonder why two that test things in lib/ are there)
* move information about tests in modules to the modules section
* move platform specific information about tests to that section
some style tidying.

p4raw-id: //depot/maint-5.8/perl@34794