[jdk11u-dev] RFR: 8215291: Broken links when generating from project without modules

[Basil Crow]

Hi all,

This pull request contains a clean backport of [JDK-8215291](https://bugs.openjdk.org/browse/JDK-8215291) (openjdk/jdk at cb553175b7c8248ab89738a7694ea72026027198).

The commit being backported was authored by @hns on December 21, 2018, and was reviewed by @jonathan-gibbons.

See [JENKINS-68761](https://issues.jenkins.io/browse/JENKINS-68761) for the motivation behind this backport.

I tested this by reproducing the search problem described in [JENKINS-68761](https://issues.jenkins.io/browse/JENKINS-68761) on `jdk11u-dev` and verified that I could no longer reproduce the problem after backporting this commit.

Thanks!

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Commit messages:
 - Backport cb553175b7c8248ab89738a7694ea72026027198

Changes: https://git.openjdk.org/jdk11u-dev/pull/1157/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1157&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8215291
  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1157.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1157/head:pull/1157

PR: https://git.openjdk.org/jdk11u-dev/pull/1157