Add D8 verification for 910-methods.

Bug: 65850560
Test: USE_D8=true art/test/run-test ... 910-methods

Object.toString looks like:

return getClass().getName() + "@" + Integer.toHexString(hashCode())

Which roughly translates to:
 StringBuilder b = new StringBuilder();
 b = b.append(getClass().getName());
 b = b.append("@");
 b = b.append(Integer.toHexString(hashCode());
 return b.toString();

D8 does not generate move-result for the 3 append() calls.

Change-Id: I5985f9c2b8bb4c89c7a3268d98115e45016df277