RFR(L) Take 2 of Valhalla support for AArch64

[Dmitry Samersoff]

Hello Everybody,

Please, review the next version of the changes against lworld branch:

http://cr.openjdk.java.net/~dsamersoff/valhalla_lworld_aarch64/webrev.04

*What is done:*

*  Shared interface changes are adopted.

*  24 tests of 24 from runtime/valhalla/valuetypes are passed.

*   11 of 14 tests from compiler/valhalla/valuetypes are passed with
ValueTypePassFieldsAsArgs=Off, ValueTypeReturnedAsFields=Off

*  Support for ValueTypePassFieldsAsArgs and ValueTypeReturnedAsFields
is implemented, but not complete.


*Open points:*

1. Tests:

  compiler/valhalla/valuetypes/TestMethodHandles.java
  compiler/valhalla/valuetypes/TestBasicFunctionality.java (partially)

  Fails because the count of ALLOC doesn't match to the count expected
by the test. I'm looking into it.


2. Support for ValueTypePassFieldsAsArgs and ValueTypeReturnedAsFields
is implemented but there are some issues

  I'll send a separate letter about it. I'll be happy if someone with
good C2 knowledge chimes in with thoughts on it

  Temporary, I forced these flags to OFF for AArch64


3. One test still fails

   compiler/valhalla/valuetypes/TestNewAcmp.java (one test within it)

   Fails with:
   Test failed: should return false


4. JNI tests doesn't run.

   Plan to address it on the next turn.


Regards,
-Dmitry