Use target.linux for all linux kernel based targets

Now in Android.bp files, target.linux applies to all targets running a
linux kernel (android, linux_glibc, linux_bionic). So common
flags/sources/etc can be combined instead of copying them to each
target.

Test: m
Change-Id: I02896fca358c7e27466d2c33e17a43f1b3af8665
diff --git a/Android.bp b/Android.bp
index b79999f..a76b782 100644
--- a/Android.bp
+++ b/Android.bp
@@ -36,10 +36,7 @@
     ],
 
     target: {
-        android: {
-            srcs: ["AsynchronousCloseMonitor.cpp"],
-        },
-        linux_glibc: {
+        linux: {
             srcs: ["AsynchronousCloseMonitor.cpp"],
         },
     },