Optimize parsing option args in load

[Watson1978]

It looked up one by one to make sure that the supported options were included in passed options. This approach of looking up the passed hash each time has an overhead.

This patch will extract key and value from the passed options using rb_hash_foreach() and check if they are supported or not.

−	before	after	result
load	640.171k	679.986k	1.062x

Environment

• MacBook Pro (M1, 2021)
• macOS 13.3.1
• Apple M1
• clang 14.0.3
• Ruby 3.2.2

Before

Warming up --------------------------------------
                load    63.538k i/100ms
Calculating -------------------------------------
                load    640.171k (± 0.2%) i/s -      3.240M in   5.061851s

After

Warming up --------------------------------------
                load    67.690k i/100ms
Calculating -------------------------------------
                load    679.986k (± 0.3%) i/s -      3.452M in   5.076904s

Test code

require 'bundler/inline'
gemfile do
  source 'https://rubygems.org'
  gem 'benchmark-ips'
  gem 'ox'
end

xml = %{
<?xml version="1.0"?>
<Park.Animal>
  <type>mutant</type>
  <friends type="Hash">
    <i>5</i>
    <Park.Animal>
      <type>dog</type>
    </Park.Animal>
  </friends>
</Park.Animal>
}

Benchmark.ips do |x|
  x.report('load') { Ox.load(xml, mode: :generic) }
end

[Watson1978]

This is similar way with ohler55/oj#683