ARM64: Share address computation across SIMD LDRs/STRs.

For array accesses the element address has the following structure:
Address = CONST_OFFSET + base_addr + index << ELEM_SHIFT

Taking into account ARM64 LDR/STR addressing modes address part
(CONST_OFFSET + index << ELEM_SHIFT) can be shared across array
access with the same data type and index.

For example, for the following loop 5 accesses can share address
computation:

void foo(int[] a, int[] b, int[] c) {
  for (i...) {
    a[i] = a[i] + 5;
    b[i] = b[i] + c[i];
  }
}

Test: test-art-host, test-art-target

Change-Id: I46af3b4e4a55004336672cdba3296b7622d815ca
diff --git a/test/527-checker-array-access-simd/info.txt b/test/527-checker-array-access-simd/info.txt
new file mode 100644
index 0000000..f147943
--- /dev/null
+++ b/test/527-checker-array-access-simd/info.txt
@@ -0,0 +1 @@
+Test arm- and arm64-specific array access optimization for simd loops.