ci/freedreno: Ban vs-clip-vertex-enables which flakes in CI.

It's reliably failing on its own, but has shown up as the top flake in CI.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8722>

.gitlab-ci.yml

@@ -1473,8 +1473,12 @@ arm64_a630_vk_sysmem:
     #
     # vs-output-array-vec2-index-wr-before-gs is skipped because it causes
     # a flood of GPU hangs and makes the rest of the job flakey
+    #
+    # vs-clip-vertex-enables skipped because it seems to be flaky in parallel with
+    # other tests (reliably fails on its own)
     PIGLIT_OPTIONS: >-
       -x vs-output-array-vec2-index-wr-before-gs
+      -x vs-clip-vertex-enables
       -x arb_blend_func_extended-fbo-extended-blend-pattern_gles2
       -x clear-accum
       -x copypixels-sync

.gitlab-ci/piglit/freedreno-a630-shader.txt

@@ -932,7 +932,6 @@ spec/glsl-1.10/execution/vsfs-unused-array-member: crash
 spec/glsl-1.10/preprocessor/extension-defined-test: skip
 spec/glsl-1.10/preprocessor/extension-if-1: skip
 spec/glsl-1.20/execution/clipping/fixed-clip-enables: fail
-spec/glsl-1.20/execution/clipping/vs-clip-vertex-enables: fail
 spec/glsl-1.30/execution/clipping/vs-clip-distance-deadcode: crash
 spec/glsl-1.30/execution/clipping/vs-clip-distance-enables: fail
 spec/glsl-1.30/execution/fs-large-local-array-vec2: crash
@@ -1128,7 +1127,7 @@ summary:
        name:  results
        ----  --------
        pass:     8878
-       fail:       32
+       fail:       31
       crash:       95
        skip:      997
     timeout:        0
@@ -1139,4 +1138,4 @@ summary:
     changes:        0
       fixes:        0
 regressions:        0
-      total:    10004
+      total:    10003