In some [1] cases where a lexical declaration is not allowed, ASI will
cause a `let` at the end of a line to be interpreted as an
identifier. A recent patch [2] to fix up the error messages from
misplaced `let` usage was a little overzealous in triggering
the error, throwing a SyntaxError in this edge case. This patch
restores the ASI behavior, which is permitted in JSC and
SpiderMonkey as well. Thanks to a test262 test from Andre Bargull
for raising this issue.

[1] https://tc39.github.io/ecma262/#sec-expression-statement
[2] https://codereview.chromium.org/2697193007

Bug: v8:3305
Change-Id: I80ae8ad9a8a93389ff1003323f0d3f003e7a8c8e
Reviewed-on: https://chromium-review.googlesource.com/529225Reviewed-by: Marja Hölttä <marja@chromium.org>
Commit-Queue: Daniel Ehrenberg <littledan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#45817}