Fix CREATE TABLE / LIKE with bigint identity column

Fix CREATE TABLE / LIKE with bigint identity column

CREATE TABLE / LIKE with a bigint identity column would fail on
platforms where long is 32 bits.  Copying the sequence values used
makeInteger(), which would truncate the 64-bit sequence data to 32 bits.
To fix, use makeFloat() instead, like the parser.  (This does not
actually make use of floats, but stores the values as strings.)

Bug: #15096
Reviewed-by: Michael Paquier <michael@paquier.xyz>