Revert of Combine webrtc/api/java/android and webrtc/api/java/src. (patchset #1 id:1 of https://codereview.webrtc.org/2111823002/ )

Reason for revert:
Breaks downstream dependencies

Original issue's description:
> Combine webrtc/api/java/android and webrtc/api/java/src.
>
> It used to be that there was a Java api for devices not running Android
> but that is no longer the case. I combined the directories and made
> the folder structure chromium style.
>
> BUG=webrtc:6067
> R=magjed@webrtc.org, tommi@webrtc.org
>
> Committed: ceefe20dd6

TBR=magjed@webrtc.org,tommi@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:6067

Review URL: https://codereview.webrtc.org/2106333005 .

Cr-Commit-Position: refs/heads/master@{#13357}

webrtc/api/api_java.gyp

@@ -34,12 +34,14 @@
             'android_manifest_path': '<(webrtc_root)/build/android/AndroidManifest.xml',
             'suppressions_file': '<(webrtc_root)/build/android/suppressions.xml',
             'chromium_code': 1,
-            'java_in_dir': 'android/java',
+            'java_in_dir': 'java',
             'webrtc_base_dir': '<(webrtc_root)/base',
             'webrtc_modules_dir': '<(webrtc_root)/modules',
             'additional_src_dirs' : [
-              '<(webrtc_base_dir)/java',
+              'java/android',
+              '<(webrtc_base_dir)/java/src',
               '<(webrtc_modules_dir)/audio_device/android/java/src',
+
             ],
           },
           'includes': ['../../build/java.gypi'],