Issue #16098:  Update heapq.nsmallest to use the same algorithm as nlargest.

This removes the dependency on bisect and it bring the pure Python code
in-sync with the C code.
Fix typo
Fix Issue #12921: BaseHTTPServer's send_error should send the correct error
response message when  send_error includes a message in addition to error
status. Patch contributed by Karl.
Fix Issue #12921: BaseHTTPServer's send_error should send the correct error
response message when  send_error includes a message in addition to error
status. Patch contributed by Karl.
Reverting the changeset 5126e62c60af made for Issue #12921
Reverting the changeset 5d76a4746d9d made for Issue #12921
#11732: add a new suppress_crash_popup() context manager to test.support.
Fix indentation.