RFR 8214309: Enhance makefiles to allow generating JCov instrumented build

[Alexandre (Shura) Iline]

Hi.

Please take a look on a suggested change in OpenJDK make system which allows to generate an image instrumented for code coverage analysis with JCov. There will need to be follow-on changes making it possible to run test with code coverage.

When —with-jcov options supplied during configuration, it is possible to use jcov-image target which generates an instrumented image in images/jdk-jcov. There is a code coverage template within it. There is also jcov-bundle target. It is also possible to instrument an external JDK image by pointing to it by --with-jcov-input-jdk configuration option.

Webrev: http://cr.openjdk.java.net/~shurailine/8214309/webrev.02

Many thanks to Erik for helping out with this change.

Shura