Monomorphic prototype failures should be reserved for already-seen keys.

We incorrectly mark a KeyedStoreIC miss as a monomorphic prototype
failure even though it's the first time a particular (string) key has
been seen.

BUG=358088
R=verwaest@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/219313002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20407 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
PreParser fix: propagate reference erros properly.

For example, invalid left hand sides are reference errors. PreParser didn't use
to produce this error ever, so the code for propagating reference errors
properly was missing, and reference errors turned into syntax errors.

R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/220233006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20408 ce2b1a6d-e550-0410-aec6-3dcde31c8c00