Remove TTS symbols from NDK stub library.

These haven't actually existed in libandroid for some time. We can't
fix the past, so just remove the API from the NDK.

Test: make checkbuild
Bug: http://b/64572149
Change-Id: Ic68e81c63e738e6d341bcae6178cdcc080326da4

native/android/libandroid.map.txt

@@ -184,11 +184,9 @@ LIBANDROID {
     ATrace_beginSection; # introduced=23
     ATrace_endSection; # introduced=23
     ATrace_isEnabled; # introduced=23
-    android_getTtsEngine; # introduced-arm=13 introduced-arm64=21 introduced-mips=13 introduced-mips64=21 introduced-x86=13 introduced-x86_64=21
     android_getaddrinfofornetwork; # introduced=23
     android_setprocnetwork; # introduced=23
     android_setsocknetwork; # introduced=23
-    getTtsEngine; # introduced-arm=13 introduced-arm64=21 introduced-mips=13 introduced-mips64=21 introduced-x86=13 introduced-x86_64=21
   local:
     *;
 };