RFR: JDK-8066761: Investigate -sourcepath usage when compiling java

[Erik Joelsson]

Hello,

Please review this fix, removing the use of -sourcepath when compiling 
java sources. For a long time, all java compilation lines have included 
a -sourcepath <srcdir> parameter. We have now concluded that in some 
cases it's just wrong and the rest of the cases it's just unnecessary.

I have tried building with and without this patch and enabling sjavac, 
and the class file output is equivalent in all cases.

Bug: https://bugs.openjdk.java.net/browse/JDK-8066761
Webrev: http://cr.openjdk.java.net/~erikj/8066761/webrev.01/

/Erik