CLTV: Add more tests to improve coverage

Four cases included:

• The CLTV operand type mismatches the tx locktime. In the script it is 1 (interpreted as block height), but in the tx is 500000000 (interpreted as date)
• The stack is empty when executing OP_CLTV
• The tx is final by having only one input with MAX_INT sequence number
• The operand for CLTV is negative (after OP_0 OP_1 OP_SUB)