Freeze two different strings to reduce String allocations
Freeze two different strings to reduce String allocations

miq-yaml.rb is responsible for creating nearly 40,000 objects when
loading the Rails environment.

By freezing the strings "<<" and "__iv__", we allocate nearly 38%
less objects in miq-yaml.rb.

```ruby
require 'allocation_tracer'

ObjectSpace::AllocationTracer.setup(%i{path line type})

result = ObjectSpace::AllocationTracer.trace do
  require './config/environment'
end

puts ObjectSpace::AllocationTracer.header.join("\t")
result.sort_by{|k, v| k}.each{|k, v|
  puts ([v[0]]+k).join("\t")
}
```

```
$ ruby benchmark_allocations.rb | grep "miq-yaml.rb" | sort -nr
20378 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 27  T_STRING
7145  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 13  T_STRING
6064  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 10  T_NODE
3032  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 10  T_ARRAY
1034  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 31  T_STRING
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 8 T_NODE
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 7 T_NODE
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 6 T_NODE
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 1 T_STRING
```

```
$ ruby benchmark_allocations.rb | grep "miq-yaml.rb" | sort -nr
13237 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 27  T_STRING
6064  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 10  T_NODE
3032  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 10  T_ARRAY
1034  /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 31  T_STRING
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 8 T_NODE
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 7 T_NODE
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 6 T_NODE
1 /Users/joerafaniello/Code/manageiq/gems/pending/util/extensions/miq-yaml.rb 1 T_STRING
```

rsevilla87/manageiq-gems-pending,rsevilla87/manageiq-gems-pending,aljesusg/manageiq-gems-pending,aljesusg/manageiq-gems-pending