Non-decimal integer literals

Non-decimal integer literals

Add support for hexadecimal, octal, and binary integer literals:

    0x42F
    0o273
    0b100101

per SQL:202x draft.

This adds support in the lexer as well as in the integer type input
functions.

Reviewed-by: John Naylor <[email protected]>
Reviewed-by: Zhihong Yu <[email protected]>
Reviewed-by: David Rowley <[email protected]>
Reviewed-by: Dean Rasheed <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/b239564c-cad0-b23e-c57e-166d883cb97d@enterprisedb.com