Change the 64 bit map address format.

Previously, the map printing in tombstones for 64 bit devices uses
a variable length value. This means that the maps are not lined up.
The new format is to print the map as 00000000'00000000 in all ways.

Also fix a bug where the backtrace_map_t did not initialize all
parameters.

Add unit tests for all of the dump_all_maps function.

Bug: 20950813
Change-Id: I30901c8a0251b00d85c4c01476b033ef8db84e32
diff --git a/include/backtrace/BacktraceMap.h b/include/backtrace/BacktraceMap.h
index 784bc03..bb18aa2 100644
--- a/include/backtrace/BacktraceMap.h
+++ b/include/backtrace/BacktraceMap.h
@@ -33,13 +33,11 @@
 #include <string>
 
 struct backtrace_map_t {
-  backtrace_map_t(): start(0), end(0), flags(0) {}
-
-  uintptr_t start;
-  uintptr_t end;
-  uintptr_t offset;
-  uintptr_t load_base;
-  int flags;
+  uintptr_t start = 0;
+  uintptr_t end = 0;
+  uintptr_t offset = 0;
+  uintptr_t load_base = 0;
+  int flags = 0;
   std::string name;
 };