Issue 38133: py.exe cannot locate Store package

The py.exe launcher cannot locate installations from the Store (unless you have no other installations on your machine, which is unlikely).

I added an "exe_display" override for listing paths, since the full path to the store app is not supposed to be used by users (it's different from sys.executable) and is only going to work when the shorter name is on PATH anyway (due to a limitation in Windows that I'm still trying to get fixed).

I also enabled support for the ExecutablePath key, which has the added benefit of making the debug py_d.exe able to find release Python 3.5+ installs (as well as finding the Store install at all, which is now using python3.8.exe as the main file because of the limitation I mentioned above).

Sample output after this change (some paths elided):

Installed Pythons found by ...\py.exe Launcher for Windows
 (venv)         C:\...\env\Scripts\python.exe *
 -3.8-64        python3.8.exe
 -3.7-32-32     C:\Python37_x86\python.exe
 -3.7-64        C:\Python37_x64\python.exe
 -3.6-32-32     C:\Python36_x86\python.exe
 -3.6-64        C:\Users\...\AppData\Local\Programs\Python\Python36\python.exe
 -3.5-32-32     C:\Python35_x86\python.exe
 -3.5-64        C:\Python35_x64\python.exe
 -3.4-64        C:\Python34_x64\python.exe
 -3.3-64        C:\Python33_x64\python.exe
 -3.3-32        C:\Python33_x86\python.exe
 -3.2-64        C:\Python32_x64\python.exe
 -3.2-32        C:\Python32_x86\python.exe
 -3.1-64        C:\Python31_x64\python.exe
 -3.1-32        C:\Python31_x86\python.exe
 -3.0-32        C:\Python30_x86\python.exe
 -2.7-64        C:\Python27_x64\python.exe
 -2.7-32        C:\Python27_x86\python.exe
 -2.6-32        C:\Python26_x86\python.exe
 -2.5-32        C:\Python25_x86\python.exe

> -3.7-32-32     C:\Python37_x86\python.exe
> -3.6-32-32     C:\Python36_x86\python.exe
> -3.5-32-32     C:\Python35_x86\python.exe

MAX_VERSION_SIZE was increased, so the INSTALLED_PYTHON version string is now the full registry key name with the "-32" suffix. If that's intentional, you'll have to account for it in show_python_list. But I don't think the "-32" suffix belongs in the version string.

Ah, good catch, I didn't notice that.

Because those are special cases, we should strip it off the version string. One day when we implement PEP 514 properly then they'll come back (and we'll probably drop the -64 suffix for consistency with the PEP).

New changeset ed93a8852d120c5a3606720edc723bf5aa6a1fc2 by Steve Dower in branch 'master':
bpo-38133: Allow py.exe launcher to locate installations from the Microsoft Store (GH-16025)
https://github.com/python/cpython/commit/ed93a8852d120c5a3606720edc723bf5aa6a1fc2

New changeset 664d56a52eb5b98ac24b2d0cd4a080ffd49fd93d by Miss Islington (bot) in branch '3.8':
bpo-38133: Allow py.exe launcher to locate installations from the Microsoft Store (GH-16025)
https://github.com/python/cpython/commit/664d56a52eb5b98ac24b2d0cd4a080ffd49fd93d

New changeset 4d202281c128e2026e78fc5f4cc752b1dafbf3ad by Steve Dower in branch 'master':
bpo-38133: Update docs to reflect fixes to py.exe launcher (GH-16791)
https://github.com/python/cpython/commit/4d202281c128e2026e78fc5f4cc752b1dafbf3ad

New changeset 42308e8b27c8023e3f9d037f5e4a8892f2dcbc48 by Miss Islington (bot) in branch '3.8':
bpo-38133: Update docs to reflect fixes to py.exe launcher (GH-16791)
https://github.com/python/cpython/commit/42308e8b27c8023e3f9d037f5e4a8892f2dcbc48