RFR: JDK-8268866: Javascript when used in an iframe cannot display search results

[Hannes Wallnöfer]

Please review a trivial fix to make javadoc search work inside an `iframe`. The fix consists in removing old code that probably stems from back when javadoc used frames and doesn't work with generic iframes. 

With the fix applied the search result is opened within the `iframe` as expected. I tested on Firefox, Chrome and Safari. Labeled `noreg-hard` as we have no way of testing browser behavior.

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Commit messages:
 - JDK-8268866: Javascript when used in an iframe cannot display search results

Changes: https://git.openjdk.java.net/jdk/pull/7594/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7594&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8268866
  Stats: 5 lines in 1 file changed: 0 ins; 4 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7594.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7594/head:pull/7594

PR: https://git.openjdk.java.net/jdk/pull/7594