[10] Review request: JDK-8193636: FX build fails with jdk-10+36 due to missing javah

[Kevin Rushforth]

Phil,

Please review the following to remove the check for the existence of 
'javah':

https://bugs.openjdk.java.net/browse/JDK-8193636
http://cr.openjdk.java.net/~kcr/8193636/webrev.00/

Thanks.

-- Kevin