java.lang.Math is missing nextUp, nextDown, nextAfter emulation

[niloc132]

Historically these were deliberately omitted, but were added in Java 6:

gwt/user/super/com/google/gwt/emul/java/lang/Math.java

Lines 35 to 42 in aabb575

	// public static double nextAfter(double start, double direction)
	// public static float nextAfter(float start, float direction)
	// public static double nextUp(double start) {
	// return nextAfter(start, 1.0d);
	// }
	// public static float nextUp(float start) {
	// return nextAfter(start,1.0f);
	// }

The addition of Double.doubleToLongBits/longBitsToDouble and Float.floatToIntBits/intBitsToFloat appears to overcome the browser limitations indicated.

Note that this comment block is misleading - nextUp should pass INFINITY values as the "direction" parameter according to the javadoc - passing 1.0 and -1.0 will result in incorrect values even in the JVM impl.

Java 8 added the nextDown method as well.

These links are only for the double variants, but each has a float overload as well:
https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#nextAfter-double-double-
https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#nextUp-double-
https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#nextDown-double-