[test] TestSharedPtr -> TestSharedPtrDbgInfoContent

Two tests cannot share the same name, because they will generate an
identical trace file. When that happens, this can lead to a race
condition where dotest fails when trying to move both files into the
trace directory, because the file has already been moved. Additionally,
the trace will have been overwritten by the test that finishes last.

llvm-svn: 359807