disable ubsan (integer_overflow)

Due to the bug in the current stringstream, CodeWriter fails to write
non-ascii characters when ubsan is on.

Bug: 174366536
Test: aidl_unittests
Test: aidlcpp system/iorap/binder/com/google/android/startop/iorap/IIorap.aidl
Change-Id: I7f9ceb69b0652f56ccfcb19fa0f24c5ceed49b65
diff --git a/code_writer_unittest.cpp b/code_writer_unittest.cpp
index 9cf462c..76a2af5 100644
--- a/code_writer_unittest.cpp
+++ b/code_writer_unittest.cpp
@@ -44,5 +44,17 @@
   EXPECT_EQ(str, "Write this and that");
 }
 
+TEST(CodeWriterTest, WorksWithNonAscii) {
+  // Due to b/174366536(basic_stringbuf implicit-conversion), the following snippet crashes
+  //   std::stringstream s;
+  //   s << "가";
+  std::string str;
+  CodeWriterPtr ptr = CodeWriter::ForString(&str);
+  CodeWriter& writer = *ptr;
+  writer << "가";
+  writer.Close();
+  EXPECT_EQ(str, "가");
+}
+
 }  // namespace aidl
 }  // namespace android