[llvm] [RISCV][VLOPT] Add vector narrowing integer right shift instructions to isSupportedInstr (PR #119602)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-x86_64-debian-fast` running on `gribozavr4` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/56/builds/14282

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/RISCV/rvv/vl-opt-op-info.mir' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /b/1/clang-x86_64-debian-fast/llvm.obj/bin/llc /b/1/clang-x86_64-debian-fast/llvm.src/llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir -o - -mtriple=riscv64 -mattr=+v -run-pass=riscv-vl-optimizer -verify-machineinstrs | /b/1/clang-x86_64-debian-fast/llvm.obj/bin/FileCheck /b/1/clang-x86_64-debian-fast/llvm.src/llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir
+ /b/1/clang-x86_64-debian-fast/llvm.obj/bin/llc /b/1/clang-x86_64-debian-fast/llvm.src/llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir -o - -mtriple=riscv64 -mattr=+v -run-pass=riscv-vl-optimizer -verify-machineinstrs
+ /b/1/clang-x86_64-debian-fast/llvm.obj/bin/FileCheck /b/1/clang-x86_64-debian-fast/llvm.src/llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir
/b/1/clang-x86_64-debian-fast/llvm.src/llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir:401:11: error: CHECK: expected string not found in input
 ; CHECK: early-clobber %x:vr = PseudoVNSRL_WV_M1 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */
          ^
<stdin>:2699:17: note: scanning from here
name: vnop_wv_vd
                ^
<stdin>:2756:2: note: possible intended match here
 early-clobber %x:vr = PseudoVNSRL_WV_M1 $noreg, $noreg, $noreg, 1, 3 /* e8 */, 0 /* tu, mu */
 ^

Input file: <stdin>
Check file: /b/1/clang-x86_64-debian-fast/llvm.src/llvm/test/CodeGen/RISCV/rvv/vl-opt-op-info.mir

-dump-input=help explains the following input dump.

Input was:
<<<<<<
             .
             .
             .
          2694:  %x:vr = PseudoVADD_VV_MF4 $noreg, $noreg, $noreg, -1, 3 /* e8 */, 0 /* tu, mu */ 
          2695:  early-clobber %y:vr = PseudoVZEXT_VF8_M1 $noreg, %x, 1, 6 /* e64 */, 0 /* tu, mu */ 
          2696:  
          2697: ... 
          2698: --- 
          2699: name: vnop_wv_vd 
check:401'0                     X error: no match found
          2700: alignment: 1 
check:401'0     ~~~~~~~~~~~~~
          2701: exposesReturnsTwice: false 
check:401'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
          2702: legalized: false 
check:401'0     ~~~~~~~~~~~~~~~~~
          2703: regBankSelected: false 
check:401'0     ~~~~~~~~~~~~~~~~~~~~~~~
          2704: selected: false 
check:401'0     ~~~~~~~~~~~~~~~~
             .
             .
             .
          2751: machineFunctionInfo: 
check:401'0     ~~~~~~~~~~~~~~~~~~~~~
...

```

</details>

https://github.com/llvm/llvm-project/pull/119602