Add benchmarks for super and zsuper calls of different types

These show gains from the recent optimization commits:

```
                        arg_splat
            miniruby:   7346039.9 i/s
     miniruby-before:   4692240.8 i/s - 1.57x  slower

                  arg_splat_block
            miniruby:   6539749.6 i/s
     miniruby-before:   4358063.6 i/s - 1.50x  slower

                   splat_kw_splat
            miniruby:   5433641.5 i/s
     miniruby-before:   3851048.6 i/s - 1.41x  slower

             splat_kw_splat_block
            miniruby:   4916137.1 i/s
     miniruby-before:   3477090.1 i/s - 1.41x  slower

                   splat_kw_block
            miniruby:   2912829.5 i/s
     miniruby-before:   2465611.7 i/s - 1.18x  slower

                   arg_splat_post
            miniruby:   2195208.2 i/s
     miniruby-before:   1860204.3 i/s - 1.18x  slower
```

zsuper only speeds up in the post argument case, because
it was already set to use splatarray false in cases where
there were no post arguments.

benchmark/vm_super_splat_calls.yml

@@ -0,0 +1,25 @@
+prelude: |
+  @a = [1].freeze
+  @ea = [].freeze
+  @kw = {y: 1}.freeze
+  @b = lambda{}
+  extend(Module.new{def arg_splat(x=0, y: 0) end})
+  extend(Module.new{def arg_splat_block(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat_block(x=0, y: 0) end})
+  extend(Module.new{def splat_kw(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_block(x=0, y: 0) end})
+
+  extend(Module.new{def arg_splat; super(1, *@ea) end})
+  extend(Module.new{def arg_splat_block; super(1, *@ea, &@b) end})
+  extend(Module.new{def splat_kw_splat; super(*@a, **@kw) end})
+  extend(Module.new{def splat_kw_splat_block; super(*@a, **@kw, &@b) end})
+  extend(Module.new{def splat_kw; super(*@a, y: 1) end})
+  extend(Module.new{def splat_kw_block; super(*@a, y: 1, &@b) end})
+benchmark:
+  arg_splat: "arg_splat"
+  arg_splat_block: "arg_splat_block"
+  splat_kw_splat: "splat_kw_splat"
+  splat_kw_splat_block: "splat_kw_splat_block"
+  splat_kw: "splat_kw"
+  splat_kw_block: "splat_kw_block"

benchmark/vm_zsuper_splat_calls.yml

@@ -0,0 +1,28 @@
+prelude: |
+  a = [1].freeze
+  ea = [].freeze
+  kw = {y: 1}.freeze
+  b = lambda{}
+  extend(Module.new{def arg_splat(x=0, y: 0) end})
+  extend(Module.new{def arg_splat_block(x=0, y: 0) end})
+  extend(Module.new{def arg_splat_post(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_splat_block(x=0, y: 0) end})
+  extend(Module.new{def splat_kw(x=0, y: 0) end})
+  extend(Module.new{def splat_kw_block(x=0, y: 0) end})
+
+  extend(Module.new{def arg_splat(x, *a) super end})
+  extend(Module.new{def arg_splat_block(x, *a, &b) super end})
+  extend(Module.new{def arg_splat_post(*a, x) super end})
+  extend(Module.new{def splat_kw_splat(*a, **kw) super end})
+  extend(Module.new{def splat_kw_splat_block(*a, **kw, &b) super end})
+  extend(Module.new{def splat_kw(*a, y: 1) super end})
+  extend(Module.new{def splat_kw_block(*a, y: 1, &b) super end})
+benchmark:
+  arg_splat: "arg_splat(1, *ea)"
+  arg_splat_block: "arg_splat_block(1, *ea, &b)"
+  arg_splat_post: "arg_splat_post(1, *ea, &b)"
+  splat_kw_splat: "splat_kw_splat(*a, **kw)"
+  splat_kw_splat_block: "splat_kw_splat_block(*a, **kw, &b)"
+  splat_kw: "splat_kw(*a, y: 1)"
+  splat_kw_block: "splat_kw_block(*a, y: 1, &b)"