CpuProfiler: replace raw position with SourcePosition for DeoptReason

CpuProfiler: replace raw position with SourcePosition for DeoptReason

Save Unknown position as zero in RelocInfo.
Remove copy constructor of SourcePosition because it is trivial.
Mechanical replace int raw_position with SourcePosition position.

BUG=452067
LOG=n

Review URL: https://codereview.chromium.org/959203002

Cr-Commit-Position: refs/heads/master@{#26916}