[Sanitizer] Specify a default value for each common runtime flag

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@194479 91177308-0d34-0410-b5e6-96231b3b80d8
Added summary info to GCDAProfiling.

This function will be called by GCOVProfiling to write and update object
and program summaries to be read in by llvm-cov.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@194499 91177308-0d34-0410-b5e6-96231b3b80d8