liblog: Add functions to reset log context

Add android_log_parser_reset and android_log_reset to reset reader/writer
log context. This allows to generate multiple log messages of the same
format without context reallocation.

Change-Id: Icb0f15855378aa4e66fc671ffefd15d9df6fee1e
diff --git a/liblog/liblog.map.txt b/liblog/liblog.map.txt
index 66670fe..015c9cb 100644
--- a/liblog/liblog.map.txt
+++ b/liblog/liblog.map.txt
@@ -53,3 +53,9 @@
     __android_log_is_loggable_len;
     __android_log_is_debuggable; # vndk
 };
+
+LIBLOG_Q {
+  global:
+    android_log_reset; #vndk
+    android_log_parser_reset; #vndk
+};