[wpimath] Clean up Java Quaternion class (#4399)

Vector.norm() and Vector.dot() were added to make the implementation
simpler and match the C++ version more closely.

wpimath/src/test/java/edu/wpi/first/math/VectorTest.java

@@ -0,0 +1,30 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+package edu.wpi.first.math;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.junit.jupiter.api.Test;
+
+class VectorTest {
+  @Test
+  void testVectorDot() {
+    var vec1 = VecBuilder.fill(1.0, 2.0, 3.0);
+    var vec2 = VecBuilder.fill(4.0, 5.0, 6.0);
+
+    assertEquals(32.0, vec1.dot(vec2));
+
+    var vec3 = VecBuilder.fill(-1.0, 2.0, -3.0);
+    var vec4 = VecBuilder.fill(4.0, -5.0, 6.0);
+
+    assertEquals(-32.0, vec3.dot(vec4));
+  }
+
+  @Test
+  void testVectorNorm() {
+    assertEquals(Math.sqrt(14.0), VecBuilder.fill(1.0, 2.0, 3.0).norm());
+    assertEquals(Math.sqrt(14.0), VecBuilder.fill(1.0, -2.0, 3.0).norm());
+  }
+}