Stop limiting the number of TSan backtrace size to 8

[kubamracek]

Summary

We currently limit the length of TSan returned backtraces to 8, which is not necessary (and a bug, most likely). Let's remove this.

[jasonmolenda]

Looks fine to me, the only reason I could think to cap it is if the method used to backtrace the thread could get stuck in a loop & provide infinite number of frames. but we could have crashed earlier than this if that happened, so I'm not concerned.

[kubamracek]

We're dealing with ValueObjects here, so assuming GetNumChildren() returns a valid number of children, I think this cannot cause any issues.

lldb/trunk/source/Plugins/InstrumentationRuntime/ThreadSanitizer/ThreadSanitizerRuntime.cpp

 )";
 
 static StructuredData::Array *
 CreateStackTrace(ValueObjectSP o,
                  const std::string &trace_item_name = ".trace") {
   StructuredData::Array *trace = new StructuredData::Array();
   ValueObjectSP trace_value_object =
       o->GetValueForExpressionPath(trace_item_name.c_str());
-  for (int j = 0; j < 8; j++) {
+  size_t count = trace_value_object->GetNumChildren();
+  for (size_t j = 0; j < count; j++) {
     addr_t trace_addr =
         trace_value_object->GetChildAtIndex(j, true)->GetValueAsUnsigned(0);
     if (trace_addr == 0)
       break;
     trace->AddItem(
         StructuredData::ObjectSP(new StructuredData::Integer(trace_addr)));
   }
   return trace;