Timestamp type mismatching between Trino and Velox

[bigPYJ1151]

For Trino:

• ShortTimestamp (a Long member, 64 bits)
• LongTimestamp (a Long member and an Int member, 96 bits)

For Velox: two Long members (128 bits)

Timestamp(Precision) type signature in Trino specification is not supported in Velox

Some related UTs are disabled in TypeSignatureTest.cpp