[wsl] restore logic of WslPath.parseWindowsUncPath: both \\wsl$\ …

…and `\\wsl.localhost\` paths should be supported regardless of Windows version (WEB-70562)

Regression after bcfeaa3bbf1d2e7f1aac349d46d0e0e73047ceed.
This also fixes `WslPathTest.parsing` test which was failing on Windows 10.

GitOrigin-RevId: dfcebc3174adeb7e37f493e140eaf2320981a4bf

platform/platform-impl/src/com/intellij/execution/wsl/WSLUtil.java

@@ -205,6 +205,20 @@ static final class WSLToolFlags {
   }
 
   static @NotNull String getUncPrefix() {
-    return SystemInfo.isWin11OrNewer ? "\\\\wsl.localhost\\" : WslConstants.UNC_PREFIX;
+    return SystemInfo.isWin11OrNewer ? DEFAULT_UNC_PREFIX : WslConstants.UNC_PREFIX;
   }
+
+  /**
+   * The default path prefix to access Linux files from Windows.
+   * This is a successor to the ` \\wsl$\` path prefix.
+   * 
+   * <li>Windows 11</li>
+   * It's available since the initial release.
+
+   * <li>Windows 10</li>
+   * It's available since Windows 10 Insider Preview Build 21354.
+   * <a href="https://blogs.windows.com/windows-insider/2021/04/07/announcing-windows-10-insider-preview-build-21354/"></a>
+   * This preview was included in Windows 10 Version 21H2 (November 2021 Update).
+   */
+  static final String DEFAULT_UNC_PREFIX = "\\\\wsl.localhost\\";
 }

platform/platform-impl/src/com/intellij/execution/wsl/WslPath.kt

@@ -27,13 +27,23 @@ data class WslPath internal constructor(private val prefix: String = WslConstant
   fun toWindowsUncPath(): String = prefix + distributionId + toSystemDependentName(linuxPath)
 
   companion object {
+
+    /**
+     * Parses a Windows UNC path and returns a `WslPath` object if successful.
+     * The path should start with `\\wsl.localhost\` or `\\wsl$\` prefix.
+     * Both prefixes are supported regardless of the preferred prefix on the particular Windows.
+     *
+     * @param windowsUncPath The Windows UNC path to be parsed.
+     * @return A `WslPath` object if the path is successfully parsed, or `null` otherwise.
+     *         On OSes not supporting WSL, the method returns null.
+     */
     @JvmStatic
     fun parseWindowsUncPath(windowsUncPath: String): WslPath? {
       if (!WSLUtil.isSystemCompatible()) return null
       val path = toSystemDependentName(windowsUncPath, '\\')
 
       val legacyWslPrefix = WslConstants.UNC_PREFIX
-      val modernWslPrefix = WSLUtil.getUncPrefix()
+      val modernWslPrefix = WSLUtil.DEFAULT_UNC_PREFIX
 
       return parseWindowsUncPath(path, legacyWslPrefix) ?: parseWindowsUncPath(path, modernWslPrefix)
     }