Change method name 'analyze' to 'loadDir', 'analyze' to 'loadFile', 'serialize' to 'saveToCache'

[pdhung3012]

The class Analyzer is used to represent Analyzer. This method named 'analyze' is to load a directory. Thus, the method name 'loadDir' is more intuitive than 'analyze'.

The class Analyzer is used to represent Analyzer. This method named 'analyze' is to load a file. Thus, the method name 'loadFile' is more intuitive than 'analyze'.

The class AstCache is used to represent AstCache. This method named 'serialize' is to save to the cache. Thus, the method name 'saveToCache' is more intuitive than 'serialize'.