Address deprecations of AlwaysValidAssumption & NeverValidAssumption

Author: eregon

src/main/java/org/truffleruby/core/module/ModuleOperations.java

@@ -36,7 +36,6 @@
 import com.oracle.truffle.api.Assumption;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.nodes.Node;
-import com.oracle.truffle.api.utilities.NeverValidAssumption;
 
 public abstract class ModuleOperations {
 
@@ -127,7 +126,7 @@ private static boolean constantExists(RubyConstant constant, ArrayList<Assumptio
             if (constant.isAutoload() && constant.getAutoloadConstant().isAutoloading()) {
                 if (assumptions != null) {
                     // Cannot cache the lookup of an autoloading constant as the result depends on the calling thread
-                    assumptions.add(NeverValidAssumption.INSTANCE);
+                    assumptions.add(Assumption.NEVER_VALID);
                 }
                 return !constant.getAutoloadConstant().isAutoloadingThread();
             } else {

src/main/java/org/truffleruby/language/methods/CallInternalMethodNode.java

@@ -16,7 +16,6 @@
 import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.nodes.NodeUtil;
 import com.oracle.truffle.api.profiles.BranchProfile;
-import com.oracle.truffle.api.utilities.AlwaysValidAssumption;
 import org.truffleruby.RubyContext;
 import org.truffleruby.builtins.CoreMethodNodeManager;
 import org.truffleruby.core.inlined.AlwaysInlinedMethodNode;
@@ -157,7 +156,7 @@ protected AlwaysInlinedMethodNode getUncachedAlwaysInlinedMethodNode(InternalMet
     protected Assumption getMethodAssumption(InternalMethod method) {
         return isSingleContext()
                 ? method.getDeclaringModule().fields.getOrCreateMethodAssumption(method.getName())
-                : AlwaysValidAssumption.INSTANCE;
+                : Assumption.ALWAYS_VALID;
     }
 
     protected int getCacheLimit() {