object-literal-sort-keys does not handle spreads well

[giladgray]

Bug Report

• TSLint version: 4.5.1
• TypeScript version: 2.2.1
• Running TSLint via: VSCode & gulp-tslint

TypeScript code being linted

const options: Tether.ITetherOptions = {
        constraints: useSmartPositioning ? [DEFAULT_CONSTRAINTS] : undefined,
        ...tetherOptions,
        attachment: getPopoverAttachment(position),
        bodyElement: fakeHtmlElement,
        classPrefix: "pt-tether",
        element,
        target,
        targetAttachment: getTargetAttachment(position),
    };

Actual behavior

constraints is marked as being out of order, wants it to appear after classPrefix (classic aphabetization), but this is not equivalent code since constraints appears in its own object before tetherOptions.

Expected behavior

spreads should break up properties into separate groups (cuz they're compiled to separate objects in __assign helper)

// compiled tsc output, modified for readability (and only key names)
var options = tslib_1.__assign(
    { constraints }, 
    tetherOptions, 
    { attachment, bodyElement, classPrefix, element, target, targetAttachment },
);