[mlgo] remove inlining_default - unused feature

The feature was only exposed for training and was immediately dropped on
the training side. It was bulk-copied into the test model generator, where
it had no effect (the generator always returns a constant).

In the AOT + test model case, since the test model returns a constant, all
input features are pruned by the AOT compiler, so its presence/absence
doesn't matter.

Author: mtrofin

llvm/lib/Analysis/DevelopmentModeInlineAdvisor.cpp

@@ -253,7 +253,6 @@ class LoggingMLInlineAdvice : public MLInlineAdvice {
 };
 
 static const std::vector<TensorSpec> TrainingOnlyFeatures{
-    TensorSpec::createSpec<int64_t>(TFFeedPrefix + "inlining_default", {1}),
     TensorSpec::createSpec<float>(TFFeedPrefix + "discount", {1}),
     TensorSpec::createSpec<float>(TFFeedPrefix + "reward", {1}),
     TensorSpec::createSpec<int32_t>(TFFeedPrefix + "step_type", {1})};

llvm/lib/Analysis/models/gen-inline-oz-test-model.py

@@ -47,7 +47,6 @@ def get_input_signature():
             "edge_count",
             "callsite_height",
             "cost_estimate",
-            "inlining_default",
             "sroa_savings",
             "sroa_losses",
             "load_elimination",