RFR(M): 8241230: JFR: Extreme value testing: initial drop

[mikhailo.seledtsov at oracle.com]

This is an initial drop for larger effort tracked by "8230571: [TESTBUG] 
JFR: Extreme value testing".
The goal of 8230571 is to create stress JFR tests using extreme values, 
such as large number of
unique events, large number of active recordings, large number of 
threads and more. See 8230571 for details.

This issue (8241230) was created for initial drop. It contains 3 tests: 
large number of unique JFR event types,
large number of active recordings and large number of strings. Goals for 
this drop are:
     - review and agree upon naming and location: location of tests, 
package name, test naming, etc.
     - review patterns used for this testing (see comments in 8241230 
for details)
     - agree upon parameterized scaling via test properties
     - and avoid "all at once" large drops

Once this change is integrated, more tests will follow as per plan 
outlined in 8241230. The tests will largely follow
naming conventions and patterns agreed for this change.


     JBS: https://bugs.openjdk.java.net/browse/JDK-8241230
     Webrev: http://cr.openjdk.java.net/~mseledtsov/8241230.00/
     Testing:
         Ran tests on Linux-x64, Win-x64 and MAC, with default stress 
level - All PASS
         Running with higher stress levels: in progress


Thank you,
Misha