[JDK-8267666](https://bugs.openjdk.java.net/browse/JDK-8267666) added a 2nd test case, which doubles the run time of this test. As a result it occasionally times out. This change double the timeout to 240 seconds.
------------- Commit messages: - Longer timeout for HeapDumpAllTest needed after new test case added. Changes: https://git.openjdk.java.net/jdk/pull/4935/files Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4935&range=00 Issue: https://bugs.openjdk.java.net/browse/JDK-8270341 Stats: 4 lines in 2 files changed: 0 ins; 1 del; 3 mod Patch: https://git.openjdk.java.net/jdk/pull/4935.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/4935/head:pull/4935 PR: https://git.openjdk.java.net/jdk/pull/4935
