This concern [dtdbuilder
tools](https://github.com/openjdk/jdk/tree/master/make/jdk/src/classes/build/tools/dtdbuilder).
In jshell, try `System.getProperty("html32") + ""` you'll get a `String`.
So, in `DTDBuilder.java` when none `dtd_home` property is set, the `dtd_home`
string value is not `null`, causing an exception with the present test.
The expect value is `"Must set property 'dtd_home'"`
And in this case, should'nt we have a `System.exit(1)` too rather than a simple
`return` ?
-------------
Commit messages:
- Change test none dtd_home property is set.
Changes: https://git.openjdk.java.net/jdk/pull/3626/files
Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3626&range=00
Issue: https://bugs.openjdk.java.net/browse/JDK-8265909
Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
Patch: https://git.openjdk.java.net/jdk/pull/3626.diff
Fetch: git fetch https://git.openjdk.java.net/jdk pull/3626/head:pull/3626
PR: https://git.openjdk.java.net/jdk/pull/3626
