Reduce the number of #includes.

CurFrame, TraceMode, and the CachedWriter are history.
ArrayChecksEnabled and non-QuietMode are history.
The ExecutionAnnotations (SlotNumber, InstNumber, and FunctionInfo) are history.
ExecutionContext now keeps Values for each stack frame in a std::map.
Stop pre-initializing Values on the stack to 42.
Remove some dead variables, excess whitespace and commented-out code.
executeInstruction() is now part of run().
printValue() and print() are history.

llvm-svn: 9489