RFR: 8237512: AArch64: aarch64TestHook leaks a BufferBlob

[Nick Gasson]

Hello,

Bug: https://bugs.openjdk.java.net/browse/JDK-8237512
Webrev: http://cr.openjdk.java.net/~ngasson/8237512/webrev.0/

aarch64TestHook() is called from ICache::initialize() and allocates a
500k BufferBlob that it passes to entry() in assembler_aarch64.cpp which
performs a self-test of the assembler. The BufferBlob needs to be
explicitly freed or else it will hang around forever. Also we can just
skip the allocation if ASSERT is not defined as the test is not
performed in this case.

java -XX:+PrintCodeCache -Xint -version before:

   CodeCache: size=49152Kb used=1427Kb max_used=1427Kb free=47724Kb

After:

   CodeCache: size=49152Kb used=940Kb max_used=940Kb free=48212Kb

Tested jtreg tier1.


Thanks,
Nick