RFR: JDK-8200358 Remove mapfiles for JDK executables

Wed Mar 28 11:08:28 UTC 2018

This patch removes mapfiles for the JDK executables (launchers). There's 
really no reason to have mapfiles in the first place for executables. 
Since no-one is linking to them, what symbols they export is immaterial.

Bug: https://bugs.openjdk.java.net/browse/JDK-8200358
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8200358-remove-launcher-mapfiles/webrev.01

/Magnus