--forever now stops if a fail changes the environment.
(cherry picked from commit 5e87592)

… from 3.6 to 3.5 (#2540)

* [3.6] bpo-29512, bpo-30776: Backport regrtest enhancements from master to 3.6 (#2513)

* bpo-29512: Add test.bisect, bisect failing tests (#2452)

Add a new "python3 -m test.bisect" tool to bisect failing tests.

It can be used to find which test method(s) leak references, leak
files, etc.
(cherry picked from commit 84d9d14)

* bpo-30776: regrtest: reduce memleak false positive (#2484)

Only report a leak if each run leaks at least one memory block.
(cherry picked from commit beeca6e)

(cherry picked from commit a3ca94d)

* bpo-30764: Fix regrtest --fail-env-changed --forever (#2536) (#2539)

--forever now stops if a fail changes the environment.
(cherry picked from commit 5e87592)
(cherry picked from commit 4132adb)

…o 2.7 (#2541)

* bpo-29512, bpo-30764: Backport regrtest enhancements from 3.5 to 2.7

* bpo-29512: Add test.bisect, bisect failing tests (#2452)

Add a new "python3 -m test.bisect" tool to bisect failing tests.

It can be used to find which test method(s) leak references, leak
files, etc.

* bpo-30764: Fix regrtest --fail-env-changed --forever (#2536) (#2539)

--forever now stops if a fail changes the environment.

* Fix test_bisect: use absolute import

* Revert "bpo-30854: Fix compile error when --without-threads (#2581)"

This reverts commit 0c31163.

* Revert "NEWS for 30777 (#2576)"

This reverts commit aaa917f.

* Revert "bpo-21624: IDLE -- minor htest fixes (#2575)"

This reverts commit 2000150.

* Revert "bpo-30777: IDLE: configdialog - add docstrings and improve comments (#2440)"

This reverts commit 7eb5883.

* Revert "bpo-30319: socket.close() now ignores ECONNRESET (#2565)"

This reverts commit 67e1478.

* Revert "bpo-30789: Use a single memory block for co_extra. (#2555)"

This reverts commit 378ebb6.

* Revert "bpo-30845: Enhance test_concurrent_futures cleanup (#2564)"

This reverts commit 3df9dec.

* Revert "bpo-29293: multiprocessing.Condition.notify() lacks parameter `n` (#2480)"

This reverts commit 4835041.

* Revert "Remove outdated FOX from GUI FAQ (GH-2538)"

This reverts commit d3ed287.

* Revert "bpo-6691: Pyclbr now reports nested classes and functions. (#2503)"

This reverts commit 246ff3b.

* Revert "bpo-29464: Rename METH_FASTCALL to METH_FASTCALL|METH_KEYWORDS and make (#1955)"

This reverts commit 6969eaf.

* Revert "bpo-30832: Remove own implementation for thread-local storage (#2537)"

This reverts commit aa0aa04.

* Revert "bpo-30764: Fix regrtest --fail-env-changed --forever (#2536)"

This reverts commit 5e87592.

* Revert "bpo-30822: Deduplicate ZoneInfoTest classes in test_datetime. (#2534)"

This reverts commit 34b5487.

* Revert "bpo-30822: Fix testing of datetime module. (#2530)"

This reverts commit 98b6bc3.