Add a test to ensure False Start occurs.

This adds the missing test coverage for
7e3305eebd7fb06d57e7f25b3bbf9c10d526f7d5.

Change-Id: I8c9f1dc998afa9bb1f6fb2a7872a651037bb4844
Reviewed-on: https://boringssl-review.googlesource.com/1610
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/test_config.cc b/ssl/test/test_config.cc
index cf0d0af..9d1ffc9 100644
--- a/ssl/test/test_config.cc
+++ b/ssl/test/test_config.cc
@@ -53,6 +53,7 @@
   { "-no-tls1", &TestConfig::no_tls1 },
   { "-no-ssl3", &TestConfig::no_ssl3 },
   { "-cookie-exchange", &TestConfig::cookie_exchange },
+  { "-shim-writes-first", &TestConfig::shim_writes_first },
 };
 
 const size_t kNumBoolFlags = sizeof(kBoolFlags) / sizeof(kBoolFlags[0]);
@@ -93,7 +94,8 @@
       no_tls11(false),
       no_tls1(false),
       no_ssl3(false),
-      cookie_exchange(false) {
+      cookie_exchange(false),
+      shim_writes_first(false) {
 }
 
 bool ParseConfig(int argc, char **argv, TestConfig *out_config) {