Missing `weatherreport-test` makefile target on Windows

[NOTE]: # ( ^^ Provide a general summary of the issue in the title above. ^^ )

## Description

The make target `weatherreport-test` is missing on Windows and needs to be backported
from the *nix makefile target.

## Steps to Reproduce

Run this on Windows:
```
PS C:\relax\couchdb> make -f Makefile.win weatherreport-test
```
Output:
```
make: *** No rule to make target 'weatherreport-test'. Stop.
```

## Expected Behaviour

Should run the test like the makefile target on *nix:
```
[ * ] Running cluster setup ... ok
[ * ] Exec command bin/weatherreport --etc dev/lib/node1/etc --level error ... No diagnostic messages to report.
```

## Your Environment

* CouchDB version used: a14922fad42575574bb26a24a123e0a1ef4e1621
* Operating system and version: Windows Server 2022

Compare the existing weatherreport-test target in the *nix makefile with Makefile.win, then run make -f Makefile.win weatherreport-test on Windows. Done means the target exists and produces the expected cluster setup and weatherreport output without the missing-rule error.

Written by the indexing model from the issue text.