Introduces fused bytecodes for fusing LdaSmi followed by a binary op bytecode.
The chosen bytecodes are used frequently in Octane: AddSmi, SubSmi,
BitwiseOrSmi, BitwiseAndSmi, ShiftLeftSmi, ShiftRightSmi.

There are additional code stubs for these operations that are biased towards
both the left hand and right hand operands being Smis.

BUG=v8:4280
LOG=N

Review-Url: https://codereview.chromium.org/2111923002
Cr-Commit-Position: refs/heads/master@{#37531}