[2.x] Use JDK's Unix domain socket for bootserver (#9427)

Use JDK's Unix domain socket for bootserver.

main/src/main/scala/sbt/Defaults.scala

@@ -402,7 +402,7 @@ object Defaults extends BuildCommon with DefExtra {
       },
       serverHandlers :== Nil,
       windowsServerSecurityLevel := Win32SecurityLevel.OWNER_DACL, // allows any owner logon session to access the server
-      serverUseJni := BootServerSocket.requiresJNI || SysProp.serverUseJni,
+      serverUseJni := SysProp.serverUseJni,
       fullServerHandlers := Nil,
       insideCI :== sys.env.contains("BUILD_NUMBER") ||
         sys.env.contains("CI") || SysProp.ci,

main/src/main/scala/sbt/Main.scala

@@ -160,7 +160,7 @@ private[sbt] object xMain:
     def liveServerDetected: Boolean =
       BootServerSocketProbe.liveServerDetected(
         BootServerSocket.socketLocation(base, hash),
-        BootServerSocket.requiresJNI() || SysProp.serverUseJni,
+        SysProp.serverUseJni,
       )
     try Some(new BootServerSocket(configuration, hash)) -> None
     catch {
@@ -183,8 +183,9 @@ private[sbt] object xMain:
           )
           (None, Some(Exit(2)))
         }
-      case _: IOException          => (None, None)
-      case _: UnsatisfiedLinkError => (None, None)
+      case _: IOException                   => (None, None)
+      case _: UnsatisfiedLinkError          => (None, None)
+      case _: UnsupportedOperationException => (None, None)
     }
   }
 end xMain