[Frontend] Parsing and analyzing the same file with a syntactic error can return different messages

[rturrado]

For instance, mistyping version as vrsion returns:

• for parsing: :1:1: mismatched input 'vrsion' expecting {NEW_LINE, ';', 'version'}, and
• for analyzing: Error: :1:1: syntax error.

[rturrado]

This is what I think it is happening here:

• libqasm analyzes v1 and v3 programs. And, in order to do that, it has a version parser, i.e., a parser that is dedicated to parsing the version only. So we first parse the version and then call the v1 or the v3 parser.
• Now, looking at the errors, it seems that the parser error comes from ANTLR, while the analyzer error comes from the version parser. I.e., the parsing API is not using the version parser, but the analyzing API is using it.
• I should have a look and see if this is an expected behaviour or not.

[rturrado]

If, in a near future, we drop v1, we may not have this issue anymore.