[9] RFR (M): 8067344: Adjust java/lang/invoke/LFCaching/LFGarbageCollectedTest.java for recent changes in java.lang.invoke

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/8067344/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-8067344

LFGarbageCollectedTest should be adjusted after JDK-8057020.

There are a couple of problems with the test.

(1) Existing logic to test that LambdaForm instance is collected isn't 
stable enough. Consequent System.GCs can hinder reference enqueueing.
To speed up the test, I added -XX:SoftRefLRUPolicyMSPerMB=0 and limited 
the heap by -Xmx64m.

(2) MethodType-based invoker caches are deliberately left strongly 
reachable. So, they should be skipped in the test.

(3) Added additional diagnostic output to simplify failure analysis 
(test case details, method handle type and LambdaForm, heap dump 
(optional, -DHEAP_DUMP=true)).

Testing: failing test.

Thanks!

Best regards,
Vladimir Ivanov