RFR (L): 8248194: Need better support for running SA tests on core files

[Chris Plummer]

[Note, the following changes only impact serviceability tests, but I am 
adding some test library code to assist with creating and finding core 
files, and I thought others on hotspot-dev might have an interest in that.]

Hello,

Please help review the following changes to add better support for 
writing SA tests that work on core files:

https://bugs.openjdk.java.net/browse/JDK-8248194
http://cr.openjdk.java.net/~cjplummer/8248194/webrev.01/index.html

As outlined in the CR, these are the 3 main goals of this CR:

1. Add a shared API for locating the path to the core file. This 
includes parsing the output of the crashed process to locate where the 
core file was saved, and returning this location to the user. This API 
will be placed in the new CoreUtils class.

2. Add a shared API to support adding the "ulimit -c unlimited" prefix 
to the command that will produce the core file, allowing the overriding 
of any lower limit so we can be sure the core file will be produced. 
This API will also be placed in the new CoreUtils class.

3. LingeredApp should include support for producing a core file.

As proof of concept for these improvements, I'm updating the following 3 
tests to make use of them:

ClhsdbCDSCore.java and TestJmapCore.java: Use the CoreUtils support 
listed above. These tests do not use LingeredApp, so those improvements 
don't apply.

ClhsdbFindPC.java: Use all the above new features, including having 
LingeredApp produce a core file. This is the only test modified to start 
testing on core files that didn't previously do so. It still also tests 
on a live process.

In the future more Clhsdb tests will be converted to work on core files 
in a manner similar to ClhsdbFindPC.

The new CoreUtils code is borrowed from (more like ripped out of) 
ClhsdbCDSCore.java and TestJmapCore.java. They both had a lot of code 
dedicated to finding the core file and also applying "ulimit -c 
unlimited", but didn't do so in quite the same way. Now both these tests 
share code in CoreUtils.java. One thing I did drop is TestJmapCore.java 
use of ":KILLED_PID" in the output to help find the core file. It's no 
longer necessary based on the smarter core locating code I pulled from 
ClhsdbCDSCore.java.

One other improvement was to enable windows support for ClhsdbCDSCore. 
The only reason it was not enabled previously is because the author 
couldn't figure out how to properly generate the command for the process 
that produces the core. Since it is launched using "sh -c", the path has 
to be converted to use forward slashes. This is now done in CoreUtils.

One other change in ClhsdbCDSCore is that it no longer renames the core 
file to a well known name in the cwd. This was unnecessary. It 
originated in code from ciReplayBase.java, which does have a reason to 
do the rename, but ClhsdbCDSCore does not.

The new libLingeredApp.c relies on JDK-8248667 [1] being in place in 
order to have the build system properly compile it. JDK-8248667 will be 
reviewed separately on build-dev and pushed just before the changes for 
this CR.

thanks,

Chris

[1] https://bugs.openjdk.java.net/browse/JDK-8248667