Add AsynchronousCloseMonitor to intra-core API.

This change also adds it to the last-api.txt for the intra-core as it
will be required as part of the long-term "stable" intra-core API in
order to run mainline Conscrypt on Android 10.  This API is unchanged
since Android 10 and so this is a backwards compatible change.

Note that AsynchronousCloseMonitor is implicitly part of the intra-core
API already as its native component is invoked from Conscrypt JNI code.

Bug: 147870945
Test: TreeHugger
Change-Id: I61c52fc1499860db887c4cce38817913536cc98a
diff --git a/non_openjdk_java_files.bp b/non_openjdk_java_files.bp
index 7b39f09..8fc3607 100644
--- a/non_openjdk_java_files.bp
+++ b/non_openjdk_java_files.bp
@@ -239,6 +239,7 @@
         "luni/src/main/java/libcore/icu/RelativeDateTimeFormatter.java",
         "luni/src/main/java/libcore/icu/TimeZoneNames.java",
         "luni/src/main/java/libcore/internal/StringPool.java",
+        "luni/src/main/java/libcore/io/AsynchronousCloseMonitor.java",
         "luni/src/main/java/libcore/io/ForwardingOs.java",
         "luni/src/main/java/libcore/io/IoBridge.java",
         "luni/src/main/java/libcore/io/IoUtils.java",
@@ -377,7 +378,6 @@
         "luni/src/main/java/libcore/icu/DateTimeFormat.java",
         "luni/src/main/java/libcore/icu/DateUtilsBridge.java",
         "luni/src/main/java/libcore/internal/Java9LanguageFeatures.java",
-        "luni/src/main/java/libcore/io/AsynchronousCloseMonitor.java",
         "luni/src/main/java/libcore/io/ClassPathURLStreamHandler.java",
         "luni/src/main/java/libcore/io/BlockGuardOs.java",
         "luni/src/main/java/libcore/io/BufferIterator.java",