The ExFileObject class was removed, some of its code went into _FileInFile.

This introduces a new function, imp.extension_suffixes(), which is
currently undocumented. That is forthcoming once issue #14657 is
resolved and how to expose file suffixes is decided.

The certificate has changed and the test now needs SNI to pass.

The certificate has changed and the test now needs SNI to pass.

The address of an object was being decreffed instead of the object.

Keep inline for performance critical functions (functions used in loops)

 * The write_str() method does nothing if the length is zero.
 * Replace "struct unicode_writer_t" with "unicode_writer_t"