RFR: 8263167: IGV: build fails with "taskdef AutoUpdate cannot be found"

[Roberto Castañeda Lozano]

As part of the [recent transition](https://netbeans.apache.org/about/oracle-transition.html) of the NetBeans project to the Apache fundation, [http://bits.netbeans.org](http://bits.netbeans.org) has stopped serving the `tasks.jar` file used to download IGV's build dependencies. This change updates the IGV build configuration to use the [nbm-maven-harness](https://mvnrepository.com/artifact/org.codehaus.mojo/nbm-maven-harness) Maven artifact instead, which provides the same functionality.

Tested manually on linux-x64.

-------------

Commit messages:
 - 8263167: IGV: build fails with "taskdef AutoUpdate cannot be found"

Changes: https://git.openjdk.java.net/jdk/pull/2869/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2869&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8263167
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2869.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2869/head:pull/2869

PR: https://git.openjdk.java.net/jdk/pull/2869