pgsql: Revert "Fix issues with Windows' stat() for files pending on del

Revert "Fix issues with Windows' stat() for files pending on deletion"

This reverts commit 54fb8c7, as per the issues reported by fairywren
when it comes to MinGW because of the lack of microsoft_native_stat()
there.  Using just stat() for MSVC is not sufficient to take care of the
concurrency problems with files pending on deletion.  It may be possible
to paint some __MINGW64__ in the code to switch to a different
implementation of stat() in this build context, but I am not sure either
if relying on the implementation of stat() in MinGW to take care of the
problems we are trying to fix is enough or not.  So this needs more
study.

Discussion: https://postgr.es/m/YOvOlfRrIO0yGtgw@paquier.xyz
Backpatch-through: 14

Branch
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REL_14_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/5e60237ad1b4e2d159aec48ffd9914a633d2d6e0

Modified Files
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src/port/open.c      |   4 +-
src/port/win32stat.c | 177 +++++++++++++++++++++++++++++++++++++--------------
2 files changed, 132 insertions(+), 49 deletions(-)