feat($compile): use allOrNothing interpolation for ngAttr*

allOrNothing interpolation is now used for ng-attr-*, under all circumstances. This prevents
uninitialized attributes from being added to the DOM with invalid values which cause errors
to be shown.

BREAKING CHANGE:

Now, ng-attr-* will never add the attribute to the DOM if any of the interpolated expressions
evaluate to `undefined`.

To work around this, initialize values which are intended to be the empty string with the
empty string:

For example, given the following markup:

    <div ng-attr-style="border-radius: {{value}}{{units}}"></div>

If $scope.value is `4`, and $scope.units is undefined, the resulting markup is unchanged:

    <div ng-attr-style="border-radius: {{value}}{{units}}"></div>

However, if $scope.units is `""`, then the resulting markup is updated:

    <div ng-attr-style="border-radius: {{value}}{{units}}" style="border-radius: 4"></div>

Closes #8376