Fix Java static colors having zero values (#2269)

Also add test for this.

wpilibj/src/test/java/edu/wpi/first/wpilibj/util/ColorTest.java

@@ -0,0 +1,50 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2020 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+package edu.wpi.first.wpilibj.util;
+
+import java.util.stream.Stream;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.assertAll;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.params.provider.Arguments.arguments;
+
+class ColorTest {
+  private static final double kEpsilon = 1e-3;
+
+  void assertColorMatches(double red, double green, double blue, Color color) {
+    assertAll(
+        () -> assertEquals(red, color.red, kEpsilon),
+        () -> assertEquals(green, color.green, kEpsilon),
+        () -> assertEquals(blue, color.blue, kEpsilon)
+    );
+  }
+
+  @ParameterizedTest
+  @MethodSource("staticColorProvider")
+  void staticColorTest(double red, double green, double blue, Color color) {
+    assertColorMatches(red, green, blue, color);
+  }
+
+  @ParameterizedTest
+  @MethodSource("staticColorProvider")
+  void colorEqualsTest(double red, double green, double blue, Color color) {
+    assertEquals(color, new Color(red, green, blue));
+  }
+
+  static Stream<Arguments> staticColorProvider() {
+    return Stream.of(
+      arguments(0.0823529412, 0.376470589, 0.7411764706, Color.kDenim),
+      arguments(0.0, 0.4, 0.7019607844, Color.kFirstBlue),
+      arguments(0.9294117648, 0.1098039216, 0.1411764706, Color.kFirstRed)
+    );
+  }
+}