feat: move OS.clock to IO.clock and remove deprecated os_clock native

Migrate the clock timing functionality from the OS class to the IO class across all benchmark scripts and the core library. Remove the os_clock native function and its associated OS class definition from wren_core.c, while adding a new ioClock native in wren_io.c that uses the same clock()/CLOCKS_PER_SEC logic. Update all benchmark files (binary_trees, fib, for, method_call) to reference IO.clock instead of OS.clock for both start time and elapsed time calculations.

benchmark/binary_trees.wren

@@ -24,7 +24,7 @@ var minDepth = 4
 var maxDepth = 12
 var stretchDepth = maxDepth + 1
 
-var start = OS.clock
+var start = IO.clock
 
 IO.print("stretch tree of depth " + stretchDepth.toString + " check: " +
     new Tree(0, stretchDepth).check.toString)
@@ -53,4 +53,4 @@ while (depth < stretchDepth) {
 IO.print("long lived tree of depth " + maxDepth.toString + " check: " +
     longLivedTree.check.toString)
 
-IO.print("elapsed: " + (OS.clock - start).toString)
+IO.print("elapsed: " + (IO.clock - start).toString)

benchmark/fib.wren

@@ -3,8 +3,8 @@ var fib = fn(n) {
   return fib.call(n - 1) + fib.call(n - 2)
 }
 
-var start = OS.clock
+var start = IO.clock
 for (i in 1..5) {
   IO.print(fib.call(28))
 }
-IO.print("elapsed: " + (OS.clock - start).toString)
+IO.print("elapsed: " + (IO.clock - start).toString)

benchmark/for.wren

@@ -1,10 +1,10 @@
 var list = []
 
-var start = OS.clock
+var start = IO.clock
 for (i in 0...1000000) list.add(i)
 
 var sum = 0
 for (i in list) sum = sum + i
 
 IO.print(sum)
-IO.print("elapsed: " + (OS.clock - start).toString)
+IO.print("elapsed: " + (IO.clock - start).toString)

benchmark/method_call.wren

@@ -28,7 +28,7 @@ class NthToggle is Toggle {
   }
 }
 
-var start = OS.clock
+var start = IO.clock
 var n = 100000
 var val = true
 var toggle = new Toggle(val)
@@ -66,4 +66,4 @@ for (i in 0...n) {
 
 IO.print(ntoggle.value)
 
-IO.print("elapsed: " + (OS.clock - start).toString)
+IO.print("elapsed: " + (IO.clock - start).toString)