This commit changes history handling of the REPL.
There were some situations were history wasn't properly saved and flushed to a
file, making history very spotty. This commit changes it to save every line into
the history file and flush it to disk before being evaluated.
Thanks to this all lines, including "close()" will be stored in the history
file.
If for any reason we're not able to save history file, a single warning will be
printed to the REPL and it will continue to work, even if subsequent tries will
fail to save to disk.
This commit adds support for "--eval-file" in "deno repl" subcommand.
This flag can be used to pass paths or URLs to files, that will be executed
on REPL startup. All files will be executed in the same context as the REPL
(ie. as "plain old scripts", not ES modules), sharing the global scope.
This feature allows to implement custom REPLs on top of Deno's REPL.
Fixes "op_set_exit_code" by sharing a single "Arc" between
all workers (via "op state") instead of having a "global" value stored in
"deno_runtime" crate. As a consequence setting an exit code is always
scoped to a tree of workers, instead of being overridable if there are
multiple worker tree (like in "deno test --jobs" subcommand).
Refactored "cli/main.rs" functions to return "Result<i32, AnyError>" instead
of "Result<(), AnyError>" so they can return exit code.
