Updated the disassembler stress tester with two new features:
Updated the disassembler stress tester with two
new features:

(1) it outputs the instruction currently being
    tested to a log file, if a path is provided

(2) if instructed, it prints the time remaining
    in the exhaustive test


git-svn-id: 4c4cc70b1ef44ba2b7963015e681894188cea27e@154205 91177308-0d34-0410-b5e6-96231b3b80d8

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