[Bug 55097] New: cmd.exe does not handle PATH with leading or sequential semicolons

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=55097

Bug ID: 55097
           Summary: cmd.exe does not handle PATH with leading or
                    sequential semicolons
           Product: Wine
           Version: unspecified
          Hardware: x86-64
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: cmd
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

Created attachment 74657
  --> https://bugs.winehq.org/attachment.cgi?id=74657
Repro program for PATH separator bug

Wine's cmd.exe doesn't properly handle PATH values with:
- A leading semicolon
- Two sequential semicolons

Windows handles this fine, as shown in the attached test program. Simply
extract and then run test.bat from cmd.exe

Output looks like such in wine:
```
Z:\home\loothelion\repos\wine-path-bug>test.bat
"Expecting failure (no print)"
Can't recognize 'test.bat' as an internal or external command, or batch script.
"Expecting SUCCESS"
"PATH=Z:\home\loothelion\repos\wine-path-bug/a"
SUCCESS
"Expecting SUCCESS (exposes WINE bug)"
"PATH=;Z:\home\loothelion\repos\wine-path-bug/a"
"Expecting SUCCESS"
"PATH=D:/;Z:\home\loothelion\repos\wine-path-bug/a"
SUCCESS
"Expecting SUCCESS (exposes WINE bug)"
"PATH=D:/;;Z:\home\loothelion\repos\wine-path-bug/a"
```

I have a fix for this that I plan to send for review shortly, as well as a new
test case to protect against regressions.