Revert the default phone number comparation algorithm.

Now developers have to explicitly set the third argument of PHONE_NUMBERS_COMPARE() into 1,
when they want to use "strict" phone number comparation algorithm, which was used in Donut.
In default, PHONE_NUMBER_COMPARE() now uses "loose" phone number comparation algorithm,
which had been used in Cupcake.

Internal issue id: 1892808