SH_PATH should be $targetsh, not $sh

Due to a small oversight, this was reverted in the last metaconfig
update, and was preventing backticks/system/exec/two-arg-pipe-open
from working in some Android devices.
Fix for [perl #121963] 5.20.0-RC1 can't compile on Android

On some native android builds, this was causing warnings and
possibly build errors before Config.pm was generated.
make regen for uconfig.h
Makefile.SH: Module::Build is no longer there, stop copying it

This only affected 'make test' for cross-compilation builds; in
those, we try to copy files relevant to 'make test' to the target
system.

Since Module::Build is no longer part of the core, no need to
try to copy it over.