[lldb] Fix TestFileHandle.lua

 - Explicitly create an `SBFile`.
 - Add missing call to `close`.
 - Use `SetErrorFile` in TestLegacyFileErr.

Author: JDevlieghere

lldb/test/API/lua_api/TestFileHandle.lua

@@ -2,7 +2,8 @@ _T = require('lua_lldb_test').create_test('TestFileHandle')
 
 function _T:TestLegacyFileOutScript()
     local f = io.open(self.output, 'w')
-    self.debugger:SetOutputFile(f)
+    local sbf = lldb.SBFile(f)
+    self.debugger:SetOutputFile(sbf)
     self:handle_command('script print(1+1)')
     self.debugger:GetOutputFileHandle():write('FOO\n')
     self.debugger:GetOutputFileHandle():flush()
@@ -15,7 +16,8 @@ end
 
 function _T:TestLegacyFileOut()
     local f = io.open(self.output, 'w')
-    self.debugger:SetOutputFile(f)
+    local sbf = lldb.SBFile(f)
+    self.debugger:SetOutputFile(sbf)
     self:handle_command('expression/x 3735928559', false)
     f:close()
 
@@ -26,8 +28,10 @@ end
 
 function _T:TestLegacyFileErr()
     local f = io.open(self.output, 'w')
-    self.debugger:SetErrorFile(f)
+    local sbf = lldb.SBFile(f)
+    self.debugger:SetErrorFile(sbf)
     self:handle_command('lol', false)
+    f:close()
 
     f = io.open(self.output, 'r')
     assertStrContains(f:read('*l'), 'is not a valid command')