[Android] remove compilation warning message about '-mno-thumb' for ARM
[Android] remove compilation warning message about '-mno-thumb' for ARM

This patch should remove "clang: warning: argument unused during compilation: '-mno-thumb'" message in below,

```
$ rake spec:device jobs=1
    Create ./build/Testing-19/AndroidManifest.xml
    Create ./build/Testing-19/testjava.jar.bridgesupport
Picked up JAVA_TOOL_OPTIONS: -Dfile.encoding=UTF8
   Compile ./app/main_activity.rb
clang: warning: argument unused during compilation: '-mno-thumb'
```

HipByte/RubyMotion,HipByte/RubyMotion,hboon/RubyMotion,HipByte/RubyMotion,hboon/RubyMotion,hboon/RubyMotion,katsuyoshi/RubyMotion,katsuyoshi/RubyMotion,katsuyoshi/RubyMotion,katsuyoshi/RubyMotion