feat: implement for-in loop syntax with iterate/iteratorValue protocol and break support

Add `for (variable in sequence)` syntax to the Wren language, introducing the `in` keyword token and compiler support for iterating over sequences using `iterate` and `iteratorValue` methods. Includes new benchmark files for Lua, Python, Ruby, and Wren, plus test cases covering single-expression bodies, block bodies, closures over loop variables, and break statements. Also fixes a missing POP() in CLOSE_UPVALUE and moves the while test file to a subdirectory.

benchmark/fib.txt

@@ -1,37 +0,0 @@
-Value is just Obj* and all values are boxed.
-→ time ../build/Release/wren fib.wren
-9.22746e+06
-
-real  0m12.688s
-user  0m12.076s
-sys 0m0.601s
-
----
-
-Unboxed singletons and numbers. Value is a struct of ValueType, double, Obj* obj.
-→ time ../build/Release/wren fib.wren
-9.22746e+06
-
-real  0m3.233s
-user  0m3.229s
-sys 0m0.003s
-
----
-
-NaN tagged values.
-→ time ../build/Release/wren fib.wren
-9.22746e+06
-
-real  0m3.100s
-user  0m3.097s
-sys 0m0.002s
-
----
-
-Hoist bytecode and IP into locals in interpret loop.
-→ time ../build/Release/wren fib.wren
-9.22746e+06
-
-real  0m2.490s
-user  0m2.487s
-sys 0m0.002s

benchmark/for.lua

@@ -0,0 +1,12 @@
+local list = {}
+for i = 0, 1999999 do
+  list[i] = i
+end
+
+local start = os.clock()
+local sum = 0
+for k, i in pairs(list) do
+  sum = sum + i
+end
+io.write(sum .. "\n")
+io.write(string.format("elapsed: %.8f\n", os.clock() - start))

benchmark/for.py

@@ -0,0 +1,10 @@
+import time
+
+list = range(0, 2000000)
+
+start = time.clock()
+sum = 0
+for i in list:
+  sum += i
+print(sum)
+print("elapsed: " + str(time.clock() - start))

benchmark/for.rb

@@ -0,0 +1,7 @@
+list = Array.new(2000000) {|i| i}
+
+start = Time.now
+sum = 0
+list.each {|i| sum += i}
+puts sum
+puts "elapsed: " + (Time.now - start).to_s

benchmark/for.wren

@@ -0,0 +1,17 @@
+var list = []
+
+{
+  var i = 0
+  while (i < 2000000) {
+    list.add(i)
+    i = i + 1
+  }
+}
+
+var start = OS.clock
+var sum = 0
+for (i in list) {
+  sum = sum + i
+}
+IO.write(sum)
+IO.write("elapsed: " + (OS.clock - start).toString)

benchmark/run_bench

@@ -30,6 +30,8 @@ BENCHMARK("fib", r"""317811
 317811
 317811""")
 
+BENCHMARK("for", r"""1999999000000""")
+
 BENCHMARK("method_call", r"""true
 false""")