Antlr4 target JavaScript ';' disappearing

Hello,
when generating a Parser with antlr4(target JavaScript), i noticed a statement like this
"{ $associativity = Associativity.YFX ; $bottom = $op.priority + 1; }" is created like:
"associativity=Associativity.YFX bottom=op,priority +1" in the same line and WITHOUT ';' character.
This broke my runtime test, I think it'is a bug or something else.
I also noticed if I put double ';' one of them appears.

Start with the ANTLR JavaScript target generation path and reproduce the reported grammar action containing two statements. Compare the generated JavaScript with the input, then run the runtime test mentioned in the report; done means statement separators are preserved and the test passes.

Written by the indexing model from the issue text.