core,eth: call frame tracing (#23087)

This change introduces 2 new optional methods; `enter()` and `exit()` for js tracers, and makes `step()` optiona. The two new methods are invoked when entering and exiting a call frame (but not invoked for the outermost scope, which has it's own methods). Currently these are the data fields passed to each of them:

    enter: type (opcode), from, to, input, gas, value
    exit: output, gasUsed, error

The PR also comes with a re-write of the callTracer. As a backup we keep the previous tracing script under the name `callTracerLegacy`. Behaviour of both tracers are equivalent for the most part, although there are some small differences (improvements), where the new tracer is more correct / has more information.

core/vm/stack.go

@@ -91,7 +91,7 @@ func (st *Stack) Print() {
 	fmt.Println("### stack ###")
 	if len(st.data) > 0 {
 		for i, val := range st.data {
-			fmt.Printf("%-3d  %v\n", i, val)
+			fmt.Printf("%-3d  %s\n", i, val.String())
 		}
 	} else {
 		fmt.Println("-- empty --")