This commit moves IO#readline to Ruby. In order to call C functions,
keyword arguments must be converted to hashes. Prior to this commit,
code like `io.readline(chomp: true)` would allocate a hash. This
commits moves the keyword "denaturing" to Ruby, allowing us to send
positional arguments to the C API and avoiding the hash allocation.
Here is an allocation benchmark for the method:
```
x = GC.stat(:total_allocated_objects)
File.open("/usr/share/dict/words") do |f|
f.readline(chomp: true) until f.eof?
end
p ALLOCATIONS: GC.stat(:total_allocated_objects) - x
```
Before this commit, the output was this:
```
$ make run
./miniruby -I./lib -I. -I.ext/common -r./arm64-darwin22-fake ./test.rb
{:ALLOCATIONS=>707939}
```
Now it is this:
```
$ make run
./miniruby -I./lib -I. -I.ext/common -r./arm64-darwin22-fake ./test.rb
{:ALLOCATIONS=>471962}
```
[Bug #19890] [ruby-core:114803]
IO#read/write_nonblock methods are defined in prelude.rb with
special private method __read/write_nonblock to reduce keyword
parameters overhead. We can move them into io.rb with builtin
functions.
Aaron Patterson
Nobuyoshi Nakada
Koichi Sasada