hs_c* files in the /tmp directory

[Baesken, Matthias]

Hello,
   recently we were running into issues with some hs jtreg tests (from ctw = "compile the world").
Those jtreg tests fill (at least  when they are running)  the  /tmp dir  with hs_c*  files .
This can  for a while lead to a full /tmp  on the test machines (which influences other processes on the machine in a bad way).
In some (hopefully seldom) bad cases (hangups/unexpected test ends) the hs_c* files even stay on the machine in the /tmp dir and fill it
over time.

Reason is the coding in CompileBroker::init_compiler_thread_log()

https://hg.openjdk.java.net/jdk/jdk/file/ddae2da329ed/src/hotspot/share/compiler/compileBroker.cpp#l1819

where the /tmp dir is used to store the hs_c* files.
Should there be an option to set an alternative directory for the storage of these files  (e.g. java.io.tmpdir  or something similar)  ?

Best regards, Matthias