[jdk18] RFR: 8278267: ARM32: several vector test failures for ASHR

[Hao Sun]

In ARM32, "VSHL (register)" instruction [1] is shared by vector left
shift and vector right shift, and the condition to distinguish them is
whether the shift count value is positve or negative. Hence, negation
operation is needed before conducting vector right shift.

For vector right shift, the shift count can be a RShiftCntV or a normal
vector node. Take test case Byte64VectorTests.java [2][3] as an example.
Note that RShiftCntV is already negated via rules "vsrcntD" and
"vsrcntX" whereas the normal vector node is NOT, since we don't know
whether a normal vector node is used as a vector shift count or not.
This is the root cause for these vector test failures.

The fix is simple, moving the negation from "vsrcntD|X" to the
corresponding vector right shift rules.

Affected rules are vsrlBB_reg and vsraBB_reg. Note that vector shift
related rules are in form of "vsAABB_CC", where
1) AA can be l (left shift), rl (logical right shift) and ra (arithmetic
  right shift).
2) BB can be 8B/16B (byte type), 4S/8S (short type), 2I/4I (int type)
  and 2L (long type).
3) CC can be reg (register case) and immI (immediate case).

Minor updates:
1) Merge "vslcntD" and "vsrcntD" into rule "vscntD", as these two rules
conduct the same duplication operation now.
2) Update the "match" primitive for vsraBB_immI rules.
3) Style issue: remove the surrounding space for "ins_pipe" primitive.

Tests:
We ran tier 1~3 tests on ARM32 platform. With this patch, previously
failed vector test cases can pass now without introducing test
regression.

[1] https://developer.arm.com/documentation/ddi0406/c/Application-Level-Architecture/Instruction-Details/Alphabetical-list-of-instructions/VSHL--register-?lang=en
[2] https://github.com/openjdk/jdk/blame/master/test/jdk/jdk/incubator/vector/Byte64VectorTests.java#L2237
[3] https://github.com/openjdk/jdk/blame/master/test/jdk/jdk/incubator/vector/Byte64VectorTests.java#L2425

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Commit messages:
 - 8278267: ARM32: several vector test failures for ASHR

Changes: https://git.openjdk.java.net/jdk18/pull/41/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk18&pr=41&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278267
  Stats: 490 lines in 1 file changed: 120 ins; 179 del; 191 mod
  Patch: https://git.openjdk.java.net/jdk18/pull/41.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18 pull/41/head:pull/41

PR: https://git.openjdk.java.net/jdk18/pull/41