[asan] split detect_odr_violation into two: =2 detects all ODR violations, =1 detects only those where the variable sizes are different. BTW, the detector seems to be working well and finding nice bugs. Early adopters are welcome.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@207415 91177308-0d34-0410-b5e6-96231b3b80d8