Add tests for logical operator "not"
Fix bug in bytecode generator with "not" logical operator

Github issue:

https://github.com/franko/luajit-lang-toolkit/issues/3
Implement boolean constants evaluation to optimize bytecode generation
Use constant boolean evaluation for all tests of expressions

Previously the rule was only applied for "not" unary operator.
Introduce helper functions in bytecode generator to simplify the code

Use the function "logical xor" and "storage bit".