MemoryIntArray: don't double close.

Oops, in the process of trying to track down a double close, I
introduced one...

This was caught by fdsan immediately when running the tests, but a
tombstone wasn't generated, due to a race with ActivityManager killing
crash_dump before it finished generating a tombstone. (b/112564871)

Bug: http://b/112405224
Test: atest MemoryIntArrayTest (looking at logcat this time...)
Change-Id: Iac154b92a945ce9ac8d0721e7bf200e73e6fb484
diff --git a/core/jni/android_util_MemoryIntArray.cpp b/core/jni/android_util_MemoryIntArray.cpp
index 2dfbe3e..b68f9ec 100644
--- a/core/jni/android_util_MemoryIntArray.cpp
+++ b/core/jni/android_util_MemoryIntArray.cpp
@@ -142,8 +142,6 @@
         jniThrowException(env, "java/io/IOException", "ashmem unpinning failed");
         return;
     }
-
-    close(fd);
 }
 
 static jint android_util_MemoryIntArray_get(JNIEnv* env, jobject clazz,