Add memory heap checks for mediaserver and audioserver

Memory heap check updated and restored to mediaserver,
added as new option to audioserver.

Requires properties to be set (example for audioserver):

$ adb shell setprop libc.debug.malloc.program audioserver
$ adb shell setprop libc.debug.malloc.options backtrace=8
$ adb shell pkill audioserver

...

and to dump:

$ adb shell dumpsys media.audio_flinger -m

Bug: 28909124
Bug: 27500825
Change-Id: Ifa8c2c02b022daf1a799ee4a1d75282a3c921763
diff --git a/media/libmediaplayerservice/MediaPlayerService.cpp b/media/libmediaplayerservice/MediaPlayerService.cpp
index f0190c4..acba6d7 100644
--- a/media/libmediaplayerservice/MediaPlayerService.cpp
+++ b/media/libmediaplayerservice/MediaPlayerService.cpp
@@ -536,7 +536,9 @@
             }
         }
         if (dumpMem) {
-            dumpMemoryAddresses(fd);
+            result.append("\nDumping memory:\n");
+            std::string s = dumpMemoryAddresses(100 /* limit */);
+            result.append(s.c_str(), s.size());
         }
         if (unreachableMemory) {
             result.append("\nDumping unreachable memory:\n");