Translate AST to Hydrogen missing position
Translate AST to Hydrogen missing position

This patch translates RelocInfo::kNoPosition to SourcePosition::Unknown()
in constructing the Hydrogen graph from the parser's output. The translation
is done to increase the flexibility of the parser to desugar more things
that don't have natural locations.

R=bmeurer@chromium.org
BUG=v8:4377
LOG=N

Review URL: https://codereview.chromium.org/1313443002

Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#30337}

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh