Fix: Add missing specialization for 'mmap' constructor.

Author: fangerer

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/MMapModuleBuiltins.java

@@ -101,10 +101,15 @@ PMMap doAnonymous(LazyPythonClass clazz, @SuppressWarnings("unused") int fd, int
         }
 
         @Specialization(guards = {"fd >= 0", "isNoValue(access)", "isNoValue(offset)"})
-        PMMap doIt(LazyPythonClass clazz, int fd, int length, Object tagname, @SuppressWarnings("unused") PNone access, @SuppressWarnings("unused") PNone offset) {
+        PMMap doFile(LazyPythonClass clazz, int fd, int length, Object tagname, @SuppressWarnings("unused") PNone access, @SuppressWarnings("unused") PNone offset) {
             return doFile(clazz, fd, length, tagname, ACCESS_DEFAULT, 0);
         }
 
+        @Specialization(guards = {"fd >= 0", "isNoValue(offset)"})
+        PMMap doFile(LazyPythonClass clazz, int fd, int length, Object tagname, int access, @SuppressWarnings("unused") PNone offset) {
+            return doFile(clazz, fd, length, tagname, access, 0);
+        }
+
         // mmap(fileno, length, tagname=None, access=ACCESS_DEFAULT[, offset])
         @Specialization(guards = "fd >= 0")
         PMMap doFile(LazyPythonClass clazz, int fd, int length, @SuppressWarnings("unused") Object tagname, @SuppressWarnings("unused") int access, long offset) {