SI-8893 Test tailcall transform for mix of tail/non-tail recursion

Another excellent test suggestion by Dear Reviewer.

After tail calls, the transform results in:

```
def tick(i: Int): Unit = {
      <synthetic> val _$this: Test.type = Test.this;
      _tick(_$this: Test.type, i: Int){
        if (i.==(0))
  ()
else
  if (i.==(42))
    {
      Test.this.tick(0);
      _tick(Test.this, i.-(1).asInstanceOf[Int]())
    }
  else
    _tick(Test.this, i.-(1).asInstanceOf[Int]()).asInstanceOf[Unit]()
      }
    };
```

We test this by mostly exercising the tail-recursive code path with
a level of recursion that would overflow the stack if we weren't
using jumps.

Author: retronym

test/files/run/t8893b.scala

@@ -0,0 +1,15 @@
+// Testing that recursive calls in tail positions are replaced with
+// jumps, even though the method contains recursive calls outside
+// of the tail position.
+object Test {
+  def tick(i : Int): Unit =
+    if (i == 0) ()
+    else if (i == 42) {
+      tick(0) /*not in tail posiiton*/
+      tick(i - 1)
+    } else tick(i - 1)
+
+  def main(args: Array[String]): Unit = {
+    tick(1000000)
+  }
+}