X87: Skip MultiReturnSelect_f32/MultiReturnSelect_f64 tests.

  The CL #39795 (https://codereview.chromium.org/2345593003 ) added MultiReturnSelect_f32/MultiReturnSelect_f64 tests.
  Because those tests need 2 float point return registers and x87 only has 1 FP return register, Those tests failed at x87 port.

  This CL skips MultiReturnSelect_f32/MultiReturnSelect_f64 tests for x87.

BUG=

Review-Url: https://codereview.chromium.org/2405743002
Cr-Commit-Position: refs/heads/master@{#40113}

test/cctest/cctest.status

@@ -291,6 +291,8 @@
   'test-run-machops/RunFloat64Tan': [SKIP],
   'test-cpu-profiler/Inlining': [SKIP],
   'test-gap-resolver/FuzzResolver': [SKIP],
+  'test-run-wasm/RunWasmCompiled_MultiReturnSelect_f32': [SKIP],
+  'test-run-wasm/RunWasmCompiled_MultiReturnSelect_f64': [SKIP],
 }],  # 'arch == x87'
 
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