Also add tests for hashing.

Patch by Brian Brazil.

close subprocess.PIPE file descriptors when the child encounters an
error prior to exec.

used for stdin/stdout/stderr pipes to the child when fork() fails.

when not expected in subprocess.Popen.wait().

handled by Python to not persist after os.fork() in the child process.

Issue #16411: Fix a bug where zlib.decompressobj().flush() might try to access previously-freed memory.

Patch by Serhiy Storchaka.

Additionally, fix a bug where a MemoryError in allocating a bytes object could
leave the decompressor object in an invalid state (with its unconsumed_tail
member being NULL).

Patch by Serhiy Storchaka.

#13301: use ast.literal_eval() instead of eval() in Tools/i18n/msgfmt.py.  Patch by Serhiy Storchaka.

Thanks to Yongzhi Pan.

Patch by Victor Stinner.

Issue #16350: Fix zlib decompressor handling of unused_data with multiple calls to decompress() after EOF.

Patch by Serhiy Storchaka.

#5057: the peepholer no longer optimizes subscription on unicode literals (e.g. u"foo"[0]) in order to produce compatible pyc files between narrow and wide builds.

#12759: sre_parse now raises a proper error when the name of the group is missing.  Initial patch by Serhiy Storchaka.