use jom to build with multiple threads

Jenkinsfile2

@@ -150,8 +150,8 @@ def pre_test_build_win() {
         cd debug
         call "C:\\Program Files (x86)\\Microsoft Visual Studio\\2017\\Community\\VC\\Auxiliary\\Build\\vcvarsall.bat" x64
         set CL=/MP8
-        cmake ../ -G "NMake Makefiles"
-        nmake || exit 8
+        cmake .. -G "NMake Makefiles JOM"
+        jom -j || exit 8
         time /t
     '''
     return 1