Move refinement storage to a separate object

Hardly any RubyModule instances will ever use these fields, so
punt them into a separate data object.

bench/bench_singleton.rb

@@ -1,5 +1,6 @@
 require 'benchmark/ips'
 
+loop {
 Benchmark.ips do |bm|
   bm.warmup = 10
   bm.report("1000 class << Object.new") {
@@ -10,3 +11,4 @@ class << Object.new; end
     end
   }
 end
+}

core/blah.txt

@@ -0,0 +1,37 @@
+
+The following files have been resolved:
+   org.awaitility:awaitility:jar:4.1.0:test
+   org.ow2.asm:asm-tree:jar:9.7.1:compile
+   com.github.jnr:jnr-ffi:jar:2.2.17:compile
+   me.qmx.jitescript:jitescript:jar:0.4.1:compile
+   joda-time:joda-time:jar:2.12.7:compile
+   com.github.jnr:jnr-enxio:jar:0.32.18:compile
+   org.jruby:jzlib:jar:1.1.5:compile
+   org.hamcrest:hamcrest:jar:2.1:test
+   org.osgi:org.osgi.core:jar:5.0.0:provided
+   com.github.jnr:jnr-constants:jar:0.10.4:compile
+   com.headius:invokebinder:jar:1.13:compile
+   junit:junit:jar:4.13.1:test
+   org.slf4j:slf4j-api:jar:1.7.12:provided
+   org.ow2.asm:asm-util:jar:9.7.1:compile
+   com.github.jnr:jnr-unixsocket:jar:0.38.23:compile
+   org.jruby.jcodings:jcodings:jar:1.0.61:compile
+   com.headius:options:jar:1.6:compile
+   com.github.jnr:jffi:jar:native:1.3.13:compile
+   org.slf4j:slf4j-simple:jar:1.7.12:test
+   org.ow2.asm:asm:jar:9.7.1:compile
+   com.github.jnr:jnr-a64asm:jar:1.0.0:compile
+   org.crac:crac:jar:1.5.0:compile
+   org.ow2.asm:asm-commons:jar:9.7.1:compile
+   org.hamcrest:hamcrest-core:jar:1.3:test
+   com.github.jnr:jnr-posix:jar:3.1.20:compile
+   org.jruby.joni:joni:jar:2.2.3:compile
+   com.headius:backport9:jar:1.13:compile
+   org.jruby:dirgra:jar:0.3:compile
+   com.github.jnr:jnr-netdb:jar:1.2.0:compile
+   org.apache.ant:ant-launcher:jar:1.9.8:provided
+   org.apache.ant:ant:jar:1.9.8:provided
+   com.github.jnr:jnr-x86asm:jar:1.0.2:compile
+   com.github.jnr:jffi:jar:1.3.13:compile
+   org.ow2.asm:asm-analysis:jar:9.7.1:compile
+