cleanup TOKEN_EQ, NE, LT & co tree generator:

- the left side of such an operator can *only* be a string
- get a rid of the while-loop and re-organize the code
  to better reflect what we're actually doing there


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@101113 13f79535-47bb-0310-9956-ffa450edef68