Add some debug utilities

This PR adds a set of debug helpers that are intended for calling only from gdb. They cross abstraction boundaries and allow quickly accessing one thing from another thing.
I expect to grow this library significantly over time to aid debugging tricky problems.
diff --git a/test/core/end2end/end2end_nosec_tests.c b/test/core/end2end/end2end_nosec_tests.c
index b162bf2..6a0032c 100644
--- a/test/core/end2end/end2end_nosec_tests.c
+++ b/test/core/end2end/end2end_nosec_tests.c
@@ -41,6 +41,8 @@
 
 #include <grpc/support/log.h>
 
+#include "src/core/ext/debug/debugger_macros.h"
+
 static bool g_pre_init_called = false;
 
 extern void authority_not_supported(grpc_end2end_test_config config);
@@ -143,6 +145,7 @@
 void grpc_end2end_tests_pre_init(void) {
   GPR_ASSERT(!g_pre_init_called);
   g_pre_init_called = true;
+  grpc_summon_debugger_macros();
   authority_not_supported_pre_init();
   bad_hostname_pre_init();
   binary_metadata_pre_init();