function validateSignedInteger( value, dtype ) {
	return ( isInteger( value ) && isSafeCast( minSignedIntegerDataType( value ), dtype ) ); // eslint-disable-line max-len
}
Verifies whether a provided value can be safely cast to a signed integer data type.

@private
@param {*} value - input value
@param {string} dtype - data type
@returns {boolean} boolean result

@example
var out = validateSignedInteger( 3, 'int32' );
// returns true

@example
var out = validateSignedInteger( 3.14, 'int32' );
// returns false