[sanitizer] found a bug by code inspection: CHECK(a=b) instead of CHECK(a==b). Was puzzled why lint did not catch it. Turns out this check was disabled for asan source. fix all cases and enable the check

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@178872 91177308-0d34-0410-b5e6-96231b3b80d8