[TIMOB-9663] iOS: Parity issue with 'NaN'

An issue has been identified during the investigation of MOD-682 having to do with how 'NaN' is converted to a string only on iOS. I have narrowed down the issue to the 'NaN' value being converted to lowercase 'nan' in certain situations. This causes an issue when the OAuth signature, for example, has been calculated based on a string value of 'NaN' but the value sent in the HTTP request is converted internally to a string value of 'nan' (ie. signature mismatch occurs). The serialization of the dictionary argument that is passed to the HTTPClient.send method is where the value is getting converted to 'nan' instead of 'NaN'. This works correctly on Android and MobileWeb, but not on iOS. I have reproduced this in the following sample application:

var a1 = NaN;
var b1 = parseInt("X", 10);
Ti.API.info("A1:" + a1);
Ti.API.info("B1:" + b1);
Ti.API.info(a1);
Ti.API.info(b1);

var y = {
	a2: NaN,
	b2: parseInt("X", 10)
};
Ti.API.info("A2:" + y.a2);
Ti.API.info("B2:" + y.b2);
Ti.API.info(y.a2);
Ti.API.info(y.b2);

The following output is generated on each of the platforms: || iOS || Android || MobileWeb || | A1: NaN | A1: NaN | A1: NaN | | B1: NaN | B1: NaN | B1: NaN | | {color:red}nan{color} | NaN | NaN | | {color:red}nan{color} | NaN | NaN | | A2: NaN | A2: NaN | A2: NaN | | B2: NaN | B2: NaN | B2: NaN | | {color:red}nan{color} | NaN | NaN | | {color:red}nan{color} | NaN | NaN | Notice that the value of 'nan' is generated when the value is being converted directly to a string and not being concatenated to another string. Some additional information regarding this issue on iOS. Given the following Objective-C code:

    NSString* test;

    NSDecimalNumber *v1 = [NSDecimalNumber notANumber];
    NSString *className = NSStringFromClass([v1 class]); 
    test = [v1 stringValue];

    NSNumber *v2 = [NSNumber numberWithDouble:NAN];
    className = NSStringFromClass([v2 class]); 
    test = [v2 stringValue];
    
    NSNumber *v3 = [NSNumber numberWithDouble:[v1 doubleValue]];
    className = NSStringFromClass([v3 class]); 
    test = [v3 stringValue];

When this is run from XCode, note the following values (in order of being set): 1. value of classname is 'NSDecimalNumber' 2. value of test is 'NaN' 3. value of classname is '__NSCFNumber' 4. value of test is 'nan' 5. value of classname is '__NSCFNumber' 6. value of test is 'nan' Not sure if that helps pinpoint the issue.