refactor: convert IO from singleton instance to static class with metaclass native methods

Replace the global `io` singleton object with a static `IO` class, moving the `write` native from the instance to the metaclass. Update all benchmark, example, and test files to use `IO.write()` instead of `io.write()`.

test/variable/global_in_initializer.wren

@@ -1,2 +1,2 @@
 var a = a == null
-io.write(a) // expect: true
+IO.write(a) // expect: true

test/variable/local_in_initializer.wren

@@ -1,5 +1,5 @@
 // skip: Variables should not be in scope in their initializer.
 {
   var a = a + 1 // expect error
-  io.write(a)
+  IO.write(a)
 }

test/variable/local_in_middle_of_block.wren

@@ -1,13 +1,13 @@
 class Foo {
   bar {
     var a = "a"
-    io.write(a) // expect: a
+    IO.write(a) // expect: a
     var b = a + " b"
-    io.write(b) // expect: a b
+    IO.write(b) // expect: a b
     var c = a + " c"
-    io.write(c) // expect: a c
+    IO.write(c) // expect: a c
     var d = b + " d"
-    io.write(d) // expect: a b d
+    IO.write(d) // expect: a b d
   }
 }
 

test/variable/local_in_nested_block.wren

@@ -1,6 +1,6 @@
 {
   var a = "outer"
   {
-    io.write(a) // expect: outer
+    IO.write(a) // expect: outer
   }
 }

test/variable/many_locals.wren

@@ -255,5 +255,5 @@
   var a253 = a252
   var a254 = a253
   var a255 = a254
-  io.write(a255) // expect: value
+  IO.write(a255) // expect: value
 }

test/variable/many_nonsimultaneous_locals.wren

@@ -259,7 +259,7 @@
     var a253 = a252
     var a254 = a253
     var a255 = a254
-    io.write(a255) // expect: value a
+    IO.write(a255) // expect: value a
   }
 
   {
@@ -519,6 +519,6 @@
     var b253 = b252
     var b254 = b253
     var b255 = b254
-    io.write(b255) // expect: value b
+    IO.write(b255) // expect: value b
   }
 }

test/variable/scope_if.wren

@@ -3,11 +3,11 @@ var a = "out"
 if (true) {
   var a = "in"
 }
-io.write(a) // expect: out
+IO.write(a) // expect: out
 
 // Create a local scope for the 'else' expression.
 var b = "out"
 if (false) "dummy" else {
   var b = "in"
 }
-io.write(b) // expect: out
+IO.write(b) // expect: out

test/variable/scope_reuse_in_different_blocks.wren

@@ -1,9 +1,9 @@
 {
   var a = "first"
-  io.write(a) // expect: first
+  IO.write(a) // expect: first
 }
 
 {
   var a = "second"
-  io.write(a) // expect: second
+  IO.write(a) // expect: second
 }

test/variable/scope_while.wren

@@ -4,4 +4,4 @@ var i = 0
 while ((i = i + 1) <= 1) {
   var a = "inner"
 }
-io.write(a) // expect: outer
+IO.write(a) // expect: outer

test/variable/shadow_and_local.wren

@@ -1,8 +1,8 @@
 {
   var a = "outer"
   {
-    io.write(a) // expect: outer
+    IO.write(a) // expect: outer
     var a = "inner"
-    io.write(a) // expect: inner
+    IO.write(a) // expect: inner
   }
 }

test/variable/shadow_global.wren

@@ -1,6 +1,6 @@
 var a = "global"
 {
   var a = "shadow"
-  io.write(a) // expect: shadow
+  IO.write(a) // expect: shadow
 }
-io.write(a) // expect: global
+IO.write(a) // expect: global

test/variable/shadow_in_initializer.wren

@@ -3,6 +3,6 @@
   var a = "outer"
   {
     var a = a + " inner"
-    io.write(a) // expect: outer inner
+    IO.write(a) // expect: outer inner
   }
 }

test/variable/shadow_local.wren

@@ -2,7 +2,7 @@
   var a = "local"
   {
     var a = "shadow"
-    io.write(a) // expect: shadow
+    IO.write(a) // expect: shadow
   }
-  io.write(a) // expect: local
+  IO.write(a) // expect: local
 }

test/variable/undefined_global.wren

@@ -1 +1 @@
-io.write(notDefined)  // expect error
+IO.write(notDefined)  // expect error

test/variable/undefined_local.wren

@@ -1,3 +1,3 @@
 fn {
-  io.write(notDefined)  // expect error
+  IO.write(notDefined)  // expect error
 }.call