Implement context function ctx_Length

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/hpy/GraalHPyContext.java

@@ -248,7 +248,8 @@ enum HPyContextMembers {
         CTX_RICHCOMPARE("ctx_RichCompare"),
         CTX_RICHCOMPAREBOOL("ctx_RichCompareBool"),
         CTX_HASH("ctx_Hash"),
-        CTX_NUMBER_CHECK("ctx_Number_Check");
+        CTX_NUMBER_CHECK("ctx_Number_Check"),
+        CTX_LENGTH("ctx_Length");
 
         private final String name;
 
@@ -537,6 +538,7 @@ private static Object[] createMembers(PythonContext context) {
         members[HPyContextMembers.CTX_RICHCOMPAREBOOL.ordinal()] = new GraalHPyRichcompare(true);
         members[HPyContextMembers.CTX_HASH.ordinal()] = new GraalHPyCallBuiltinFunction(BuiltinNames.HASH, 1, GraalHPyConversionNodeSupplier.TO_INT64);
         members[HPyContextMembers.CTX_NUMBER_CHECK.ordinal()] = new GraalHPyIsNumber();
+        members[HPyContextMembers.CTX_LENGTH.ordinal()] = new GraalHPyCallBuiltinFunction(BuiltinNames.LEN, 1, GraalHPyConversionNodeSupplier.TO_INT64);
         return members;
     }