adapted algorithm that selects the Java runtime to be used so that
Java installations associated with the JAVA_HOME and PATH
environment variables are preferred over others

Java installations are now analysed in the following order:
* installation that the JAVA_HOME environment
    variable refers to (if it is set)
* Java installations in PATH
* other Java installation (algorithm that was used before)
Signed-off-by: Stephan Bergmann <sbergman@redhat.com>

Conflicts:
	jvmfwk/source/framework.cxx

Change-Id: I3a3ade25322def0c0432b369848f13a6b82034a1