Merge pull request #4053 from dgquintas/bb_readall

Removed consts to make MSVC happy

test/core/surface/byte_buffer_reader_test.c

@@ -185,8 +185,8 @@ static void test_byte_buffer_from_reader(void) {
 }
 
 static void test_readall(void) {
-  const char* lotsa_as[512];
-  const char* lotsa_bs[1024];
+  char* lotsa_as[512];
+  char* lotsa_bs[1024];
   gpr_slice slices[2];
   grpc_byte_buffer *buffer;
   grpc_byte_buffer_reader reader;