[ASan] Minor documentation fix: clarify static linking limitation.
[ASan] Minor documentation fix: clarify static linking limitation.

Summary:
ASan does not support statically linked binaries, but ASan runtime itself can
be statically linked into a target binary executable.

Reviewers: eugenis, kcc

Reviewed By: eugenis

Subscribers: cfe-commits, llvm-commits

Differential Revision: https://reviews.llvm.org/D55066

git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@348863 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang