TestClangASTContext: Rewrite an if-else chain into a switch
TestClangASTContext: Rewrite an if-else chain into a switch

This avoids the "ambiguous else" warning, which comes from within the
EXPECT_TRUE macro.

git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@351331 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-lldb,apple/swift-lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,apple/swift-lldb,llvm-mirror/lldb,llvm-mirror/lldb,apple/swift-lldb