RFR(S) 8252311: AArch64: save two words in itable lookup stub

[Boris Ulasevich]

Hi,

The interface method lookup stub becomes hot when interface calls
are performed frequently. The stub assembly code can be made
shorter (132->124 bytes) by using a pre-increment instruction variant.

http://cr.openjdk.java.net/~bulasevich/8252311/webrev.00
http://bugs.openjdk.java.net/browse/JDK-8252311

The benchmark [1] shows [2] performance and icache loads improvement:
performance: 6165206 -> 6307798 ops/s
L1-icache-loads: 307.271 -> 274.604

The change was tested with JTREG.

thanks,
Boris

[1] http://cr.openjdk.java.net/~bulasevich/8252311/InvokeInterface.java
[2] http://cr.openjdk.java.net/~bulasevich/8252311/InvokeInterface.perf.txt