templater: do not preprocess template string in "if" expression (issue4714) The problem was spotted at 5ab28a2e9962, that says "this patch invokes it with "strtoken='rawstring'" in "_evalifliteral()", because "t" is the result of "arg" evaluation and it should be "string-escape"-ed if "arg" is "string" expression." This workaround is no longer valid since 890845af1ac2 introduced strict parsing of '\{'. Instead, we should interpret bare token as "string" or "rawstring" template. This is what buildmap() does at parsing phase.