Avoid exception heapdump file must have .hprof extention

Since Java 8 8u141 Update heap dump names have to end with the prefix
`hprof`.

@see Release Notes:
http://www.oracle.com/technetwork/java/javase/8u141-relnotes-3720385.html

This commit adds a Java System Property to override this check.
A permanent solution will be implemented with:

Bug 535730 - Add postfix 'hprof' to Virgo heap dumps
10 files changed