Broken code in AbstractHost (develop branch)

[marcus-h]

It seems that the AbstractHost class got broken in commit
6216f5c ("Allow concurrent handling of tags").
For instance, calling the public AbstractHost.removeTag(...) method raises the
following exception:

java.lang.RuntimeException: Unsupported; this is a bad idea concurrently
    at soot.util.ConcurrentList.remove(ConcurrentList.java:91)
    at soot.tagkit.AbstractHost.removeTag(AbstractHost.java:64)
    ...

We could probably "fix" element removal by using mTagList.iterator()
(instead of using loops that depend on mTagList.size()).

But to be honest, I do not really understand the commit at all: for instance,
if two different threads call AbstractHost.addTag(...) on the same instance,
both threads could execute the

    if (mTagList == null) {
      mTagList = new ConcurrentList<Tag>();

codepath. Is this the intended behavior?

[MarcMil]

You're right, I'll have to rework some more stuff.