build: do not "exit" a script meant to be "source"d

Running exit in a script meant to be sourced means the user shell will
exit, which prevents seeing the error message, and is generally very
annoying.
Fix the "android-configure" script to use "return" instead of "exit".

PR-URL: https://github.com/nodejs/node/pull/35520
Fixes: https://github.com/nodejs/node/issues/35519


Reviewed-By: Michaël Zasso <targos@protonmail.com>