windows-packages | use curl.exe to speed up fetching the source tarball

Tests shown that powershell's curl is an alias for `Invoke-WebRequest`
which is very slow. Use `curl.exe` instead.

A quick test showed a 2s download (curl) vs. 153s (pwsh).

```
PS C:\Users\Administrator\Downloads> Remove-Item 70266_mariadb-12.3.3.tar.gz -ErrorAction Ignore
PS C:\Users\Administrator\Downloads>
PS C:\Users\Administrator\Downloads> Measure-Command {
>>     curl.exe -L --progress-bar `
>>         https://ci.mariadb.org/70266/mariadb-12.3.3.tar.gz `
>>         -o 70266_mariadb-12.3.3.tar.gz
>> }
################################################################################################################ 100.0%

Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 1
Milliseconds      : 983
Ticks             : 19834524
TotalDays         : 2.2956625E-05
TotalHours        : 0.000550959
TotalMinutes      : 0.03305754
TotalSeconds      : 1.9834524
TotalMilliseconds : 1983.4524

PS C:\Users\Administrator\Downloads> Remove-Item 70266_mariadb-12.3.3.tar.gz -ErrorAction Ignore
PS C:\Users\Administrator\Downloads>
PS C:\Users\Administrator\Downloads> Measure-Command {
>>     Invoke-WebRequest `
>>         -Uri "https://ci.mariadb.org/70266/mariadb-12.3.3.tar.gz" `
>>         -OutFile "70266_mariadb-12.3.3.tar.gz"
>> }

Days              : 0
Hours             : 0
Minutes           : 2
Seconds           : 33
Milliseconds      : 892
Ticks             : 1538929733
TotalDays         : 0.0017811686724537
TotalHours        : 0.0427480481388889
TotalMinutes      : 2.56488288833333
TotalSeconds      : 153.8929733
TotalMilliseconds : 153892.9733
```

Author: RazvanLiviuVarzaru

master-nonlatent/master.cfg

@@ -352,9 +352,8 @@ f_windows_msi.addStep(
         command=[
             "dojob",
             '"',
-            "powershell",
-            "-command",
-            "curl",
+            "curl.exe",
+            "-L",
             util.Interpolate(
                 os.environ["ARTIFACTS_URL"]
                 + "/%(prop:tarbuildnum)s/%(prop:mariadb_version)s.tar.gz"