[vectorIntrinsics] RFR: 8266720: Wrong implementation in LibraryCallKit::inline_vector_shuffle_iota

[Wang Huang]

Because JDK-8266317 has not been merged into jdk/jdk. So I fix this bug here.
* This comparsion should be a unsigned cmp
*  `x86` is not wrong because `x86` does not have 1024-bits vl here. 
  ```c++

    ConINode* pred_node = (ConINode*)gvn().makecon(TypeInt::make(BoolTest::ge)); // should BoolTest::ugt
    Node * lane_cnt  = gvn().makecon(TypeInt::make(num_elem));
    Node * bcast_lane_cnt = gvn().transform(VectorNode::scalar2vector(lane_cnt, num_elem, type_bt));
    // should BoolTest::ugt
    Node* mask = gvn().transform(new VectorMaskCmpNode(BoolTest::ge, bcast_lane_cnt, res, pred_node, vt));

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Commit messages:
 - fix format
 - 8266720: Wrong implementation in LibraryCallKit::inline_vector_shuffle_iota

Changes: https://git.openjdk.java.net/panama-vector/pull/81/files
 Webrev: https://webrevs.openjdk.java.net/?repo=panama-vector&pr=81&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8266720
  Stats: 136 lines in 7 files changed: 102 ins; 0 del; 34 mod
  Patch: https://git.openjdk.java.net/panama-vector/pull/81.diff
  Fetch: git fetch https://git.openjdk.java.net/panama-vector pull/81/head:pull/81

PR: https://git.openjdk.java.net/panama-vector/pull/81