Revert bootstrapping to non-ASCII platforms

This effectively reverts commit 3ded5eb052cdc3f861ec0c0ff85348086d653be0.

That commit created a scheme to bootstrap Perl onto a non-ASCII
platform, by adding the allowing a Configure option that caused the
compiled code to bypass a number of normal macro definitions and use
slower, generic ones, sufficient to get miniperl to compile on the
target architecture.  One would then use miniperl to run a few scripts
that would re-order certain header files,  Using this one could then
recompile all of perl, and once that was done, use it to recompile to
use the normal fast macros.

This worked, but was a cumbersome process.  We now have the
infrastructure, since commit 6ff677df5d6fe0f52ca0b6736f8b5a46ac402943,
to cross compile on an ASCII platform to EBCDIC, the likely only
non-ASCII character set to ever be used.  So the new infrastructure will
be used in future commits.