Add check for valid state in reader next as well

I realized the text reader also throws an error when the user tries
to get the next value from within the container. That seems right
to me as well, so I added a check there and then a test to prove
consistency.

ionc/ion_reader_binary.c

@@ -149,6 +149,9 @@ iERR _ion_reader_binary_next(ION_READER *preader, ION_TYPE *p_value_type)
         value_start = ion_stream_get_position(preader->istream); // the field name isn't part of the value
         ION_GET(preader->istream, type_desc_byte);               // read the TID byte
         if (type_desc_byte == EOF) {
+            if (value_start < binary->_local_end) {
+                FAILWITH(IERR_EOF);
+            }
             goto at_eof;
         }
 

test/test_ion_binary.cpp

@@ -636,12 +636,20 @@ TEST(IonBinaryBlob, CanFullyReadBlobUsingPartialReads) {
 TEST(IonContainers, IncompleteContainerIsError) {
     hREADER reader = NULL;
     ION_TYPE type;
-    ION_ASSERT_OK(ion_test_new_reader((BYTE*)"\xE0\x01\x00\xEA\xB6", 5, &reader));
+
+    // runs same steps against text to prove consistency
+    ION_ASSERT_OK(ion_test_new_reader((BYTE*)"[", 1, &reader));
     ION_ASSERT_OK(ion_reader_next(reader, &type));
     ASSERT_EQ(tid_LIST, type);
     ION_ASSERT_OK(ion_reader_step_in(reader));
+    ION_ASSERT_FAIL(ion_reader_next(reader, &type));
+    ION_ASSERT_FAIL(ion_reader_step_out(reader));
+
+    ION_ASSERT_OK(ion_test_new_reader((BYTE*)"\xE0\x01\x00\xEA\xB2", 5, &reader));
     ION_ASSERT_OK(ion_reader_next(reader, &type));
-    ASSERT_EQ(tid_EOF, type);
+    ASSERT_EQ(tid_LIST, type);
+    ION_ASSERT_OK(ion_reader_step_in(reader));
+    ION_ASSERT_FAIL(ion_reader_next(reader, &type));
     ION_ASSERT_FAIL(ion_reader_step_out(reader));
 }