In the earlier implementation of GenerateDoubleToObject the context
is loaded from the parent's frame. rsi is clobbered because it is used
to store kHoleNan constnat. It is not always safe to peek at
the parents frame. Bytecode handlers have TypedFrame and the type of
frame is stored at FP + 1. GenerateDoubleToObject expects context
to be store at that place. In the current implementation rsi is pushed
onto the stack and is popped when exiting this function.
BUG=v8:4280,chromium:597565
LOG=N
Review URL: https://codereview.chromium.org/1848473002
Cr-Commit-Position: refs/heads/master@{#35163}
