[test-suite] 7zip CMake fix.

Use clang alias for narrowing flag so that it is recognized by the GCC compiler

Reviewed By: Meinersbur

Differential Revision: https://reviews.llvm.org/D93155
diff --git a/MultiSource/Benchmarks/7zip/CMakeLists.txt b/MultiSource/Benchmarks/7zip/CMakeLists.txt
index 6504fda..7e61aa3 100644
--- a/MultiSource/Benchmarks/7zip/CMakeLists.txt
+++ b/MultiSource/Benchmarks/7zip/CMakeLists.txt
@@ -1,6 +1,6 @@
 set(RUN_OPTIONS b)
 list(APPEND CFLAGS -DBREAK_HANDLER -DUNICODE -D_UNICODE -I${CMAKE_CURRENT_SOURCE_DIR}/C -I${CMAKE_CURRENT_SOURCE_DIR}/CPP/myWindows -I${CMAKE_CURRENT_SOURCE_DIR}/CPP/include_windows -I${CMAKE_CURRENT_SOURCE_DIR}/CPP -I. -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DNDEBUG -D_REENTRANT -DENV_UNIX -D_7ZIP_LARGE_PAGES -pthread)
-list(APPEND CXXFLAGS -Wno-error=c++11-narrowing -DBREAK_HANDLER -DUNICODE -D_UNICODE -I${CMAKE_CURRENT_SOURCE_DIR}/C -I${CMAKE_CURRENT_SOURCE_DIR}/CPP/myWindows -I${CMAKE_CURRENT_SOURCE_DIR}/CPP/include_windows -I${CMAKE_CURRENT_SOURCE_DIR}/CPP -I. -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DNDEBUG -D_REENTRANT -DENV_UNIX -D_7ZIP_LARGE_PAGES -pthread)
+list(APPEND CXXFLAGS -Wno-error=narrowing -DBREAK_HANDLER -DUNICODE -D_UNICODE -I${CMAKE_CURRENT_SOURCE_DIR}/C -I${CMAKE_CURRENT_SOURCE_DIR}/CPP/myWindows -I${CMAKE_CURRENT_SOURCE_DIR}/CPP/include_windows -I${CMAKE_CURRENT_SOURCE_DIR}/CPP -I. -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -DNDEBUG -D_REENTRANT -DENV_UNIX -D_7ZIP_LARGE_PAGES -pthread)
 list(APPEND LDFLAGS -pthread)
 set(NO_REFERENCE_OUTPUT 1)
 llvm_multisource(7zip-benchmark