revise defer to use heap allocations when running a variable number of times

testdata/calls.go

@@ -41,6 +41,9 @@ func main() {
 	// deferred functions
 	testDefer()
 
+	// defers in loop
+	testDeferLoop()
+
 	// Take a bound method and use it as a function pointer.
 	// This function pointer needs a context pointer.
 	testBound(thing.String)
@@ -85,6 +88,12 @@ func testDefer() {
 	println("deferring...")
 }
 
+func testDeferLoop() {
+	for j := 0; j < 4; j++ {
+		defer deferred("loop", j)
+	}
+}
+
 func deferred(msg string, i int) {
 	println(msg, i)
 }

testdata/calls.txt

@@ -4,6 +4,10 @@ Thing.Print: foo arg: bar
 ...run as defer 3
 ...run closure deferred: 4
 ...run as defer 1
+loop 3
+loop 2
+loop 1
+loop 0
 bound method: foo
 thing inside closure: foo
 inside fp closure: foo 3