[hal] Convert DutyCycle Raw output to be a high time measurement (#4466)

The existing raw time has an issue where it jumps around, as in the FPGA if the frequency is not a multiple or divisor of 25 Mhz it jumps around by 1 every second. While waiting on an FPGA change, update the API to make raw output give nanoseconds rather then a scaled value. This does a longer read cycle to get the correct value, but in the future if a fast FPGA function is added this can be easily changed.

hal/src/main/java/edu/wpi/first/hal/DutyCycleJNI.java

@@ -13,7 +13,7 @@ public class DutyCycleJNI extends JNIWrapper {
 
   public static native double getOutput(int handle);
 
-  public static native int getOutputRaw(int handle);
+  public static native int getHighTime(int handle);
 
   public static native int getOutputScaleFactor(int handle);