Major update to branch predictor

Created by: rosethompson

Significant performance improvements to branch predictor. Solved several bugs with btb's valid bit and ghr corruption on branch class misprediction.

• Optomized gshare.
• BTB cleanup.
• Found minor bug in gshare.
• Updated gitflow.
• More btb cleanup.
• Added logic to forward btb prediction results.
• Fixed subtle bug in btb.
• Cleaned up branch predictor.
• More branch predictor improvements.
• Improved RAS.
• Improved RAS again.
• RAS is now compliant with our header and documentation guide.
• Fixed typos.
• Intermediate commit. Passes regression tests, but RAS is not correct.
• Modified the RAS to correctly repair itself.
• Improved no class prediction mode.
• Fixed compressed branch class decode.
• Fixed another bug with the compressed instruction class decode.
• Changed the performance counters to track different data. Now rather than tracking jump(r) we track jump(r) and taken branches.
• Very hacky. But I think gshare is now correct with respect to repair on instruction class miss prediction.
• Found issue with branch predictor.
• Removed pessimistic x propagation issue for wally32priv test in the branch predictor.
• Clarified gshare bp.
• Possible fix for speculative gshare.
• Possible workign instruction class prediction repair.
• Found an issue where the btb was not forwarding the valid bit!
• Added another performance counter to track overall branch miss-predictions.
• Fixed bug with the new csr.
• Fixed another bug with the speculative gshare with instruction class prediction.
• Fixed bug with the btb's valid bit not beind held on a stall.
• Updated testbench for branch logger.
• Fixed bug in the branch logger.
• Fixed another bug with the branch logger.
• Fixed typo in testbench branch logger.
• Updated benchmark parsing script.
• Found bug in gshare.
• Gshare cleanup.
• gshare cleanup.