Issue #5637: Add attribute Integer.nearestFloat.

The Java implementation is a simple cast, the JavaScript implementation does the same as `Number.float` (i.e. calls `Float(this.valueOf())`.

language/runtime-js/numbers.js

@@ -216,6 +216,8 @@ atr$(JSNum$proto, 'character', function(){
   }
   return Character(this.valueOf());
 },undefined,function(){return{an:function(){return[shared(),actual()]},mod:$CCMM$,$cont:Integer,d:['$','Integer','$at','character']};});
+atr$(JSNum$proto, 'nearestFloat', function(){ return Float(this.valueOf()); },
+  undefined,function(){return{an:function(){return[shared(),actual()]},mod:$CCMM$,$cont:Integer,d:['$','Integer','$at','nearestFloat']};});
 atr$(JSNum$proto, 'successor', function(){ return this+1; },
   undefined,function(){return{an:function(){return[shared(),actual()]},mod:$CCMM$,$cont:Ordinal,d:['$','Ordinal','$at','successor']};});
 atr$(JSNum$proto, 'predecessor', function(){ return this-1; },

language/runtime/ceylon/language/Integer.java

@@ -428,6 +428,15 @@ public static double getFloat(long value) {
         }
     }
 
+    public double getNearestFloat() {
+        return (double) value;
+    }
+
+    @Ignore
+    public static double getNearestFloat(long value) {
+        return (double) value;
+    }
+
     public byte getByte() {
         return getByte(value);
     }

language/src/ceylon/language/Integer.ceylon

@@ -146,7 +146,17 @@ shared native final class Integer(Integer integer)
         "if the number cannot be represented as a `Float`
          without loss of precision")
     shared native Float float;
-
+
+    "The nearest [[Float]] to this number. For
+     Integers in magnitude less than 2^53, this is always
+     a Float with the exact same mathematical value (and the
+     same value as [[float]]), for larger ones on the JVM the
+     Floats are less dense than the Integers so there can be some
+     loss of precision.
+
+     This method never throws an OverflowException."
+    shared native Float nearestFloat;
+
     shared actual native Integer predecessor;
     shared actual native Integer successor;
     shared actual native Integer neighbour(Integer offset);