RFR: 8225543: Jcmd fails to attach to the Java process on Linux using the main class name if whitespace options were used to launch the process

[Daniil Titov]

Please review the change that fixes jcmd process name matching on Linux platform.

After changes [3] , on Linux platform the proc filesystem is used to find a Java process, however, sun.tools.ProcessHelper  class, 
introduced in that change, didn't take into account the presence of module whitespace options ( e.g. --patch-module) or the 
fact that some values of Java options could contain whitespaces.

The latter problem is fixed by keeping '\0' as a separator for command line arguments read from /proc/{pid}/cmdline rather than 
replacing it with a whitespace. The former problem is fixed by making sun.tools.ProcessHelper  aware of these module whitespace
 options (--add-opens, --add-exports,--add-reads, --add-modules, --patch-module,--limit-modules, or --upgrade-module-path) as well
 as of the case when a source-file mode is used or when --module options is used in "--<name>=<value>" format.

Testing: sun/tools/jcmd and serviceability/dcmd/framework tests succeeded in Mach5. jdk_svc, tier1, tier2, and tier3 tests are in progress. 


[1] Webrev: http://cr.openjdk.java.net/~dtitov/8225543/webrev.01/ 
[2] Bug: https://bugs.openjdk.java.net/browse/JDK-8225543 
[3]  https://bugs.openjdk.java.net/browse/JDK-8205654 

Thanks!
--Daniil