[GWP_ASAN] Avoid using VERSION_GREATER_EQUAL in cmake files

This is a fixup for r369823 which introduced the use of
VERSION_GREATER_EQUAL in the cmake config for gwp_asan.

Minimum supported version of cmake in LLVM is 3.4.3 and
VERSION_GREATER_EQUAL was not introduced until later
versions of cmake.

llvm-svn: 369891

compiler-rt/lib/gwp_asan/CMakeLists.txt

@@ -107,7 +107,7 @@ if (COMPILER_RT_HAS_GWP_ASAN)
   # is >= 6.0.
   if (COMPILER_RT_BUILD_LIBFUZZER AND
       "${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang" AND
-      CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 6.0)
+      NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 6.0)
     add_executable(stack_trace_compressor_fuzzer
         stack_trace_compressor_fuzzer.cpp
         ${GWP_ASAN_SOURCES}