ExecutionEngine::create no longer takes a TraceMode argument.

CurFrame, TraceMode, and the CachedWriter are history.
The ExecutionAnnotations (SlotNumber, InstNumber, and FunctionInfo) are history.
ExecutionContext now keeps Values for each stack frame in a std::map.
printValue() and print() are history.
executeInstruction() is now part of run().

llvm-svn: 9493