Bug(logql): Linefilters doesn't work well with or expressions

[kavirajk]

This PR added support for or expression to linefilters, making it easy to queries like following without using |~ regexp matcher.

{job="varlogs"} |= "foo" or "bar"

instead of

{job="varlogs"} |~ "foo|bar"

But looks like it breaks when we have multiple linefilters.

example, {job="varlogs"} != "test" != "foo" or "bar"

behaving like {job="varlogs"} != "test" != "bar" (buggy)

instead of {job="varlogs"} != "test" != "foo" != "bar" (correct. !(A || B) => !A && !B)

Have a working example in this gist.

My feeling is, when introducing the PR to support this, we probably missed supporting nested linefilters in linefilters grammer.

lineFilters:
    lineFilter                { $$ = $1 }
  | lineFilter OR orFilter    { $$ = newOrLineFilter($1, $3)}
  | lineFilters lineFilter    { $$ = newNestedLineFilterExpr($1, $2) }
  ;