Bug 842419 (part 1) - Remove unnecessary JSOp arg from EmitBackPatchOp().  r=jorendorff.

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extra : rebase_source : 1066edf46cc5c34cd79a9b021b0e5cd36dfd2403
Bug 842419 (part 2) - Remove unnecessary SRC_CONTINUE notes, and kill off PNX_ENDCOMMA.  r=jorendorff.

--HG--
extra : rebase_source : bd8c6665824d428aa7a01ff2d77ae872abaac282
Bug 842419 (part 3) - Remove dead JOF_* constants, and kill off JSOP_BACKPATCH_POP.  r=jorendorff.

--HG--
extra : rebase_source : 5b478653eee7113cf8a5c7574febbaabf63a7d70
Bug 842419 (part 4) - Clean up srcnote constants and js_SrcNoteSpec.  r=jorendorff.

--HG--
extra : rebase_source : 2340657e4bdd1a0c47151ffdc0b6ad55f6b99792
Bug 842419 (part 5) - Reduce the arity of SRC_IF_ELSE from 2 to 1.  r=jorendorff.

--HG--
extra : rebase_source : f892b0ca7e18f48332156f6c541a3bc6696b7332
Bug 842419 (part 6) - Reduce the arity of three loop-related srcnotes, and remove another.  r=jorendorff.

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extra : rebase_source : 1bd7092dd1bd116752c2817844e7351448b91d4d
Bug 842419 (part 7) - Split SRC_SWITCH in two.  r=jorendorff.

--HG--
extra : rebase_source : c91557416354c9d8003ce9f1b481c09d7eca867b
Bug 842419 (part 8) - Reduce the arity of SRC_CATCH from 1 to 0.  r=jorendorff.

--HG--
extra : rebase_source : 25b167dbbe39c673b9b7b66ef09b2d33e923c2a7