[vector] Intrinsics for fromByteArray, fromByteBuffer, intoByteArray, intoByteBuffer

[Vladimir Ivanov]

> http://cr.openjdk.java.net/~rlupusoru/panama/webrev_frombytearr_01/

src/jdk.incubator.vector/share/classes/jdk/incubator/vector/X-VectorBits.java.template

-                               (arr, idx, v) -> v.forEach((i, a_) -> 
(($type$[])arr)[idx + i] = a_));
+                               (arr, idx) -> super.intoArray(($type$[]) 
arr, idx));

After that change C2 can't eliminate vector box anymore in 
Vector.intoArray() case: the lambda captures "this" vector and, though 
the lambda isn't used and goes away during EA, that usage keeps the box 
from elimination.

Best regards,
Vladimir Ivanov