Add benchmark for yield vs proc.call

Calculating -------------------------------------
               yield     70018 i/100ms
          block.call     42809 i/100ms
-------------------------------------------------
               yield  1099624.2 (±7.3%) i/s -    5531422 in   5.056107s
          block.call   604006.1 (±7.1%) i/s -    3039439 in   5.058794s

benchmark/proc-call-vs-yield

@@ -0,0 +1,14 @@
+require 'benchmark/ips'
+
+def fast
+  yield
+end
+
+def slow(&block)
+  block.call
+end
+
+Benchmark.ips do |x|
+  x.report('yield') { fast { (0..9).to_a } }
+  x.report('block.call') { slow { (0..9).to_a } }
+end