feat: add wrenGetValueDouble API and benchmark for wrenCall() performance

Add a new public API function wrenGetValueDouble() to extract numeric values from WrenValue handles, with proper assertions for NULL and type checking. Introduce a comprehensive benchmark test for wrenCall() that measures invocation overhead by calling a foreign method 1,000,000 times across a separate VM instance, validating result correctness and reporting elapsed time. Include the benchmark script api_call.wren and register it in the Python benchmarking harness. Also fix minor assertion message typos in wren_vm.c for consistency.

test/api/benchmark.c

@@ -1,4 +1,5 @@
 #include <string.h>
+#include <time.h>
 
 #include "benchmark.h"
 
@@ -14,9 +15,56 @@ static void arguments(WrenVM* vm)
   wrenSetSlotDouble(vm, 0, result);
 }
 
+const char* testScript =
+"class Test {\n"
+"  static method(a, b, c, d) { a + b + c + d }\n"
+"}\n";
+
+static void call(WrenVM* vm)
+{
+  int iterations = (int)wrenGetSlotDouble(vm, 1);
+  
+  // Since the VM is not re-entrant, we can't call from within this foreign
+  // method. Instead, make a new VM to run the call test in.
+  WrenConfiguration config;
+  wrenInitConfiguration(&config);
+  WrenVM* otherVM = wrenNewVM(&config);
+  
+  wrenInterpret(otherVM, testScript);
+  
+  WrenValue* method = wrenGetMethod(otherVM, "main", "Test", "method(_,_,_,_)");
+  
+  double startTime = (double)clock() / CLOCKS_PER_SEC;
+  
+  double result = 0;
+  for (int i = 0; i < iterations; i++)
+  {
+    WrenValue* resultValue;
+    wrenCall(otherVM, method, &resultValue, "dddd", 1.0, 2.0, 3.0, 4.0);
+    result += wrenGetValueDouble(otherVM, resultValue);
+    wrenReleaseValue(otherVM, resultValue);
+  }
+  
+  double elapsed = (double)clock() / CLOCKS_PER_SEC - startTime;
+  
+  wrenReleaseValue(otherVM, method);
+  wrenFreeVM(otherVM);
+  
+  if (result == (1.0 + 2.0 + 3.0 + 4.0) * iterations)
+  {
+    wrenSetSlotDouble(vm, 0, elapsed);
+  }
+  else
+  {
+    // Got the wrong result.
+    wrenSetSlotBool(vm, 0, false);
+  }
+}
+
 WrenForeignMethodFn benchmarkBindMethod(const char* signature)
 {
   if (strcmp(signature, "static Benchmark.arguments(_,_,_,_)") == 0) return arguments;
+  if (strcmp(signature, "static Benchmark.call(_)") == 0) return call;
 
   return NULL;
 }

test/api/main.c

@@ -64,7 +64,7 @@ static WrenForeignClassMethods bindForeignClass(
 }
 
 static void afterLoad(WrenVM* vm) {
-  if (strstr(testName, "call.wren") != NULL) callRunTests(vm);
+  if (strstr(testName, "/call.wren") != NULL) callRunTests(vm);
 }
 
 int main(int argc, const char* argv[])

test/benchmark/api_call.wren

@@ -0,0 +1,9 @@
+class Benchmark {
+  foreign static call(iterations)
+}
+
+var result = Benchmark.call(1000000)
+// Returns false if it didn't calculate the right value. Otherwise returns the
+// elapsed time.
+System.print(result is Num)
+System.print("elapsed: %(result)")