RFR: 8333684: C2 SuperWord: multiple smaller refactorings in preparation for JDK-8332163 [v3]

[Emanuel Peter]

> In preparation for https://github.com/openjdk/jdk/pull/19261, I made some smaller refactorings / moving code around:
> 
> - `SuperWord::same_input` -> `PackSet::isa_unique_input_or_null`
> - Rename print-method tags: `SUPERWORD1_BEFORE_SCHEDULE` -> `AUTO_VECTORIZATION1_BEFORE_APPLY` etc.
> - Refactored `SuperWord::schedule / output` -> `SuperWord::schedule_and_apply`:
>   - Reorganize so that we can separate out all methods that change the C2 graph into `SuperWord::apply`.
>   - Move all `phase()->C->print_method` to `SuperWord::apply`.
>   - Rename `SuperWord::schedule_reorder_memops` -> `SuperWord::apply_memops_reordering_with_schedule`.
>   - Rename `SuperWord::output` -> `SuperWord::apply_vectorization`.
> - Move `SuperWord::vectors_should_be_aligned` -> `VLoop::vectors_should_be_aligned`.
> - Move `SuperWord::requires_long_to_int_conversion` -> `VectorNode::is_scalar_op_that_returns_int_but_vector_op_returns_long`, and move comments.
> - Move `VectorNode::can_transform_shift_op` -> `VectorNode::can_use_RShiftI_instead_of_URShiftI`, and move comments.
> - Extract out `PackSet::get_bool_test` from `SuperWord::output / apply_vectorization`.
> - Extract opcode check to `VectorNode::is_scalar_unary_op_with_equal_input_and_output_types`.

Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:

  for Christian

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/19573/files
  - new: https://git.openjdk.org/jdk/pull/19573/files/3fc32265..ccf873c1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19573&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19573&range=01-02

  Stats: 42 lines in 3 files changed: 1 ins; 0 del; 41 mod
  Patch: https://git.openjdk.org/jdk/pull/19573.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19573/head:pull/19573

PR: https://git.openjdk.org/jdk/pull/19573