Fix the usage of `embed_elixir` in escript.build
Merge pull request #2502 from alco/escript-embed-elixir

Fix the usage of `embed_elixir` in escript.build
IO.(bin)read with :all never return :eof

It returns empty string, not :eof.
And changed tests.
Ensure we don't loop when printing inspect failures, closes #2503
Merge branch 'master' of https://github.com/elixir-lang/elixir into io-read-all