PPC: skip unsupported liftoff tests

Liftoff is temporarily disabled on PPC.
After https://crrev.com/c/3202593 the newly skipped tests
are failing with this error:
```
Check failed: tester.native_module()->GetCode(0)->is_liftoff()
```

Change-Id: I681a27930909fd6ac4e5087c2d03608b891a6066
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3208070Reviewed-by: Clemens Backes <clemensb@chromium.org>
Commit-Queue: Milad Fa <mfarazma@redhat.com>
Cr-Commit-Position: refs/heads/main@{#77265}

test/cctest/cctest.status

@@ -534,6 +534,8 @@
   'test-gc/RunWasmLiftoff*': [SKIP],
   'test-run-wasm-module/Run_WasmModule_CompilationHintsNoTiering': [SKIP],
   'test-wasm-serialization/TierDownAfterDeserialization': [SKIP],
+  'test-streaming-compilation/SingleThreadedTestIncrementalCaching': [SKIP],
+  'test-streaming-compilation/AsyncTestIncrementalCaching': [SKIP],
 }],
 
 ##############################################################################