RFR: JDK-8187676: Disable uninitialized warnings for two files until proper fix available

[Erik Joelsson]

Hello,

In preparation for upgrading the toolchains used at Oracle, we need the 
build to be clean with the new compiler versions. On Linux, we are 
currently aiming at GCC 7.3. In hotspot, two files generate warnings 
when using this compiler. I found this issue already filed with a patch 
for disabling the warnings and the related issue JDK-8160404 which will 
deal with actually fixing the problem. I would like to push the 
disabling of the warnings ASAP so that the compiler upgrade project can 
continue unhindered.

Bug: https://bugs.openjdk.java.net/browse/JDK-8187676

Webrev: http://cr.openjdk.java.net/~ehelin/8187676/00/

/Erik