Add a Kokoro build config for the clang_opt.

Also move it in the git tree from quiche/kokoro to kokoro/

PiperOrigin-RevId: 478844448

build/source_list.json

diff --git a/build/source_list.json b/build/source_list.json
index 3914bca..db01f1e 100644
--- a/build/source_list.json
+++ b/build/source_list.json
@@ -945,11 +945,6 @@
   "io_tool_support_hdrs": [
     "quiche/common/platform/api/quiche_event_loop.h",
     "quiche/common/platform/api/quiche_udp_socket_platform_api.h",
-    "quiche/quic/core/batch_writer/quic_batch_writer_base.h",
-    "quiche/quic/core/batch_writer/quic_batch_writer_buffer.h",
-    "quiche/quic/core/batch_writer/quic_batch_writer_test.h",
-    "quiche/quic/core/batch_writer/quic_gso_batch_writer.h",
-    "quiche/quic/core/batch_writer/quic_sendmmsg_batch_writer.h",
     "quiche/quic/core/io/event_loop_connecting_client_socket.h",
     "quiche/quic/core/io/event_loop_socket_factory.h",
     "quiche/quic/core/io/quic_default_event_loop.h",
@@ -957,7 +952,6 @@
     "quiche/quic/core/io/quic_poll_event_loop.h",
     "quiche/quic/core/io/socket.h",
     "quiche/quic/core/quic_default_packet_writer.h",
-    "quiche/quic/core/quic_linux_socket_utils.h",
     "quiche/quic/core/quic_packet_reader.h",
     "quiche/quic/core/quic_syscall_wrapper.h",
     "quiche/quic/core/quic_udp_socket.h",
@@ -977,17 +971,12 @@
     "quiche/quic/tools/quic_server.h"
   ],
   "io_tool_support_srcs": [
-    "quiche/quic/core/batch_writer/quic_batch_writer_base.cc",
-    "quiche/quic/core/batch_writer/quic_batch_writer_buffer.cc",
-    "quiche/quic/core/batch_writer/quic_gso_batch_writer.cc",
-    "quiche/quic/core/batch_writer/quic_sendmmsg_batch_writer.cc",
     "quiche/quic/core/io/event_loop_connecting_client_socket.cc",
     "quiche/quic/core/io/event_loop_socket_factory.cc",
     "quiche/quic/core/io/quic_default_event_loop.cc",
     "quiche/quic/core/io/quic_poll_event_loop.cc",
     "quiche/quic/core/io/socket_posix.cc",
     "quiche/quic/core/quic_default_packet_writer.cc",
-    "quiche/quic/core/quic_linux_socket_utils.cc",
     "quiche/quic/core/quic_packet_reader.cc",
     "quiche/quic/core/quic_syscall_wrapper.cc",
     "quiche/quic/core/quic_udp_socket_posix.cc",
@@ -1282,10 +1271,6 @@
 
   ],
   "io_tests_srcs": [
-    "quiche/quic/core/batch_writer/quic_batch_writer_buffer_test.cc",
-    "quiche/quic/core/batch_writer/quic_batch_writer_test.cc",
-    "quiche/quic/core/batch_writer/quic_gso_batch_writer_test.cc",
-    "quiche/quic/core/batch_writer/quic_sendmmsg_batch_writer_test.cc",
     "quiche/quic/core/chlo_extractor_test.cc",
     "quiche/quic/core/http/end_to_end_test.cc",
     "quiche/quic/core/http/quic_spdy_client_session_test.cc",
@@ -1295,7 +1280,6 @@
     "quiche/quic/core/io/quic_all_event_loops_test.cc",
     "quiche/quic/core/io/quic_poll_event_loop_test.cc",
     "quiche/quic/core/io/socket_test.cc",
-    "quiche/quic/core/quic_linux_socket_utils_test.cc",
     "quiche/quic/tools/quic_default_client_test.cc",
     "quiche/quic/tools/quic_server_test.cc",
     "quiche/quic/tools/quic_simple_server_session_test.cc",
@@ -1539,5 +1523,30 @@
   "libevent_srcs": [
     "quiche/quic/bindings/quic_libevent.cc",
     "quiche/quic/bindings/quic_libevent_test.cc"
+  ],
+  "linux_only_hdrs": [
+    "quiche/quic/core/batch_writer/quic_batch_writer_base.h",
+    "quiche/quic/core/batch_writer/quic_batch_writer_buffer.h",
+    "quiche/quic/core/batch_writer/quic_batch_writer_test.h",
+    "quiche/quic/core/batch_writer/quic_gso_batch_writer.h",
+    "quiche/quic/core/batch_writer/quic_sendmmsg_batch_writer.h",
+    "quiche/quic/core/quic_linux_socket_utils.h"
+  ],
+  "linux_only_srcs": [
+    "quiche/quic/core/batch_writer/quic_batch_writer_base.cc",
+    "quiche/quic/core/batch_writer/quic_batch_writer_buffer.cc",
+    "quiche/quic/core/batch_writer/quic_gso_batch_writer.cc",
+    "quiche/quic/core/batch_writer/quic_sendmmsg_batch_writer.cc",
+    "quiche/quic/core/quic_linux_socket_utils.cc"
+  ],
+  "linux_only_tests_hdrs": [
+
+  ],
+  "linux_only_tests_srcs": [
+    "quiche/quic/core/batch_writer/quic_batch_writer_buffer_test.cc",
+    "quiche/quic/core/batch_writer/quic_batch_writer_test.cc",
+    "quiche/quic/core/batch_writer/quic_gso_batch_writer_test.cc",
+    "quiche/quic/core/batch_writer/quic_sendmmsg_batch_writer_test.cc",
+    "quiche/quic/core/quic_linux_socket_utils_test.cc"
   ]
 }
\ No newline at end of file