RFR: JDK-8141444 Clean up building of JDK launchers

[Magnus Ihse Bursie]

The JDK launchers have been built by a macro which is using positional 
arguments instead of named argument. This needs to be fixed to be able 
to properly track what is happening.

Some additional TLC for launchers is also needed.
To verify the fix, I've used the new COMPARE_BUILD feature.

Bug: https://bugs.openjdk.java.net/browse/JDK-8141444
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8141444-clean-up-launchers/webrev.01

/Magnus