[8u] RFA for 8185628: Backport jdk/test/lib/testlibrary/CompilerUtils.java to jdk8u which is helpful in test development

[Bhanu Prakash Gopularam]

Hi all,

May I get the approval for following utility test class backport 'JDK-8185628: Backport jdk/test/lib/testlibrary/CompilerUtils.java to jdk8u'. This class is quite useful for new test development in jdk8u.
Webrev link: http://cr.openjdk.java.net/~bgopularam/8185628/webrev.00/  

New changes in 8u:
For compiling java source file I have used ProcessTools.executeCommand(..) instead of JavaCompiler.CompilationTask as some of the related API (for example: JavaFileManager.setLocationFromPaths(..)) are not available in 8u.

JDK-9 Changeset: http://hg.openjdk.java.net/jdk9/jdk9/jdk/file/b2a69d66dc65/test/lib/testlibrary/CompilerUtils.java
JDK-9 review thread: I could not find specific email thread in mailer as this utility class was pushed along with module implementation in JDK-9.

Thanks,
Bhanu