RFR 8027434: "-XX:OnOutOfMemoryError" uses fork instead of vfork

[Muthusamy Chinnathambi]

Hi all,

Could you review this fix for JDK-8027434 - to use vfork instead of fork for -XX:OnOutOfMemoryError.

See bug comments for more details.

Bug URL: https://bugs.openjdk.java.net/browse/JDK-8027434 
Webrev URL: http://cr.openjdk.java.net/~mchinnathamb/8027434/webrev.00/ 

Tested with mach5 hs-tier1-4.

Regards,
Muthusamy C