Fix bug in alltypes test case that made fuzzing difficult.

tests/alltypes/decode_alltypes.c

@@ -23,6 +23,7 @@ bool check_alltypes(pb_istream_t *stream, int mode)
     
     /* Fill with garbage to better detect initialization errors */
     memset(&alltypes, 0xAA, sizeof(alltypes));
+    alltypes.extensions = 0;
     
     if (!pb_decode(stream, AllTypes_fields, &alltypes))
         return false;

tests/alltypes_callback/decode_alltypes_callback.c

@@ -220,6 +220,7 @@ bool check_alltypes(pb_istream_t *stream, int mode)
     
     /* Fill with garbage to better detect initialization errors */
     memset(&alltypes, 0xAA, sizeof(alltypes));
+    alltypes.extensions = 0;
     
     alltypes.req_int32.funcs.decode = &read_varint;
     alltypes.req_int32.arg = (void*)-1001;

tests/alltypes_pointer/decode_alltypes_pointer.c

@@ -19,6 +19,7 @@ bool check_alltypes(pb_istream_t *stream, int mode)
     
     /* Fill with garbage to better detect initialization errors */
     memset(&alltypes, 0xAA, sizeof(alltypes));
+    alltypes.extensions = 0;
     
     if (!pb_decode(stream, AllTypes_fields, &alltypes))
         return false;

tests/field_size_16/alltypes.proto

@@ -107,5 +107,7 @@ message AllTypes {
     // Just to make sure that the size of the fields has been calculated
     // properly, i.e. otherwise a bug in last field might not be detected.
     required int32      end = 10099;
+
+    extensions 200 to 255;
 }
 

tests/field_size_32/alltypes.proto

@@ -107,5 +107,7 @@ message AllTypes {
     // Just to make sure that the size of the fields has been calculated
     // properly, i.e. otherwise a bug in last field might not be detected.
     required int32      end = 13432099;
+
+    extensions 200 to 255;
 }