[gn build] Port 56762b7

Author: llvmgnsyncbot

llvm/utils/gn/secondary/clang-tools-extra/clang-tidy/bugprone/BUILD.gn

@@ -99,6 +99,7 @@ static_library("bugprone") {
     "UndelegatedConstructorCheck.cpp",
     "UnhandledExceptionAtNewCheck.cpp",
     "UnhandledSelfAssignmentCheck.cpp",
+    "UnintendedCharOstreamOutputCheck.cpp",
     "UniquePtrArrayMismatchCheck.cpp",
     "UnsafeFunctionsCheck.cpp",
     "UnusedLocalNonTrivialVariableCheck.cpp",