Fix memory-leak warnings from the static analyzer

Warnings:
frameworks/base/core/jni/android_view_InputChannel.cpp:145:5: warning:
Potential memory leak
jobject serverChannelObj =
android_view_InputChannel_createInputChannel(env,
^~~~~~~~~~~~~~~~~~~~~~~~
frameworks/base/core/jni/android_view_InputChannel.cpp:151:5: warning:
Potential memory leak
jobject clientChannelObj =
android_view_InputChannel_createInputChannel(env,
^~~~~~~~~~~~~~~~~~~~~~~~

The warnings were complaining about that we might leak
nativeInputChannel, in android_view_InputChannel_createInputChannel,
since we're allocating it as an arg and not always putting it somewhere.

Bug: None
Test: Builds without warnings
Change-Id: I62163adee5d420ad78c8d4c74aafefc8a58f765b