add java android demo (#1454)

android/SherpaOnnxJavaDemo/build.gradle

@@ -0,0 +1,9 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+plugins {
+    id 'com.android.application' version '7.2.2' apply false
+    id 'com.android.library' version '7.2.2' apply false
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}