Add `RunFor*` variants for `Cycles` and `Millis` functions

Signed-off-by: Michael Richters <gedankenexperimenter@gmail.com>

testing/SimHarness.h

@@ -29,9 +29,16 @@ class SimHarness {
  public:
   void RunCycle();
   void RunCycles(size_t n);
+  void RunForCycles(size_t n) {
+    RunCycles(n);
+  }
+
   void RunMillis(size_t t) {
     RunCycles(t);
   }
+  void RunForMillis(size_t t) {
+    RunMillis(t);
+  }
 
   void Press(KeyAddr key_addr);
   void Release(KeyAddr key_addr);