Revert of change most cases of variable redeclaration from TypeError to SyntaxError (patchset #8 id:140001 of https://codereview.chromium.org/2048703002/ )

Reason for revert:
This is going to break the LayoutTest inspector-protocol/console/console-let-const-with-api.html as seen in https://build.chromium.org/p/tryserver.v8/builders/v8_linux_blink_rel/builds/2247 . Please run this test manually, using instructions at https://www.chromium.org/developers/testing/webkit-layout-tests , and fix on the Chrome side if needed before resubmitting this patch.

Original issue's description:
> change most cases of variable redeclaration from TypeError to SyntaxError.
>
> Code like `let a; eval("var a;");` should throw a SyntaxError, not a TypeError
> (this caused a test262 failure.). However, the code `eval("function NaN() {}");`
> should actually throw a TypeError. This patch changes most cases of
> redeclaration errors from TypeError to SyntaxError. See the test
> mjsunit/regress/redeclaration-error-types for a thorough analysis with spec
> references.
>
> The relevant sections of the spec are ES#sec-globaldeclarationinstantiation and
> ES#sec-evaldeclarationinstantiation
>
> BUG=v8:4955
> LOG=y
>
> Committed: https://crrev.com/2b787561763d0f7e8dab698652715a742cf78291
> Cr-Commit-Position: refs/heads/master@{#36940}

TBR=adamk@chromium.org,jwolfe@igalia.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4955

Review-Url: https://codereview.chromium.org/2064793002
Cr-Commit-Position: refs/heads/master@{#36941}