[CI] Migrate more B200 jobs to b200-k8s queue (#42356)

Signed-off-by: khluu <khluu000@gmail.com>

.buildkite/test_areas/kernels.yaml

@@ -242,7 +242,7 @@ steps:
 - label: Kernels FusedMoE Layer Test (2 B200s)
   key: kernels-fusedmoe-layer-test-2-b200s
   timeout_in_minutes: 90
-  device: b200
+  device: b200-k8s
   num_devices: 2
   source_file_dependencies:
   - csrc/quantization/cutlass_w8a8/moe/

.buildkite/test_areas/lm_eval.yaml

@@ -92,7 +92,7 @@ steps:
 
 - label: MoE Refactor Integration Test (B200 DP - TEMPORARY)
   key: moe-refactor-integration-test-b200-dp-temporary
-  device: b200
+  device: b200-k8s
   optional: true
   num_devices: 2
   commands:
@@ -127,7 +127,7 @@ steps:
 - label: GPQA Eval (GPT-OSS) (B200)
   key: gpqa-eval-gpt-oss-b200
   timeout_in_minutes: 120
-  device: b200
+  device: b200-k8s
   optional: true
   num_devices: 2
   source_file_dependencies:

.buildkite/test_areas/spec_decode.yaml

@@ -100,7 +100,7 @@ steps:
 
 - label: Spec Decode MTP hybrid (B200)
   timeout_in_minutes: 30
-  device: b200
+  device: b200-k8s
   optional: true
   source_file_dependencies:
     - vllm/v1/spec_decode/