Remove unused assumption 'singleNativeContext'

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/PythonContext.java

@@ -169,7 +169,6 @@
 import com.oracle.graal.python.util.PythonUtils;
 import com.oracle.graal.python.util.ShutdownHook;
 import com.oracle.graal.python.util.Supplier;
-import com.oracle.truffle.api.Assumption;
 import com.oracle.truffle.api.CallTarget;
 import com.oracle.truffle.api.CompilerAsserts;
 import com.oracle.truffle.api.CompilerDirectives;
@@ -179,7 +178,6 @@
 import com.oracle.truffle.api.HostCompilerDirectives.InliningCutoff;
 import com.oracle.truffle.api.RootCallTarget;
 import com.oracle.truffle.api.ThreadLocalAction;
-import com.oracle.truffle.api.Truffle;
 import com.oracle.truffle.api.TruffleContext;
 import com.oracle.truffle.api.TruffleContext.Builder;
 import com.oracle.truffle.api.TruffleFile;
@@ -729,8 +727,6 @@ PythonThreadState getThreadState(Node n) {
 
     private TruffleString soABI; // cache for soAPI
 
-    private static final Assumption singleNativeContext = Truffle.getRuntime().createAssumption("single native context assumption");
-
     private static final class GlobalInterpreterLock extends ReentrantLock {
         private static final long serialVersionUID = 1L;
 
@@ -2224,10 +2220,6 @@ public void initializeMainModule(TruffleString path) {
         }
     }
 
-    public static Assumption getSingleNativeContextAssumption() {
-        return singleNativeContext;
-    }
-
     public boolean isExecutableAccessAllowed() {
         return getEnv().isHostLookupAllowed() || isNativeAccessAllowed();
     }