Revert of Parse arrow functions at proper precedence level (patchset #2 id:60001 of https://codereview.chromium.org/1286383005/ )

Reason for revert:
Breaks layout test. Please change test expectation on blink first.

--- /mnt/data/b/build/slave/V8-Blink_Linux_64/build/layout-test-results/inspector/sources/debugger-pause/debugger-pause-in-internal-expected.txt
+++ /mnt/data/b/build/slave/V8-Blink_Linux_64/build/layout-test-results/inspector/sources/debugger-pause/debugger-pause-in-internal-actual.txt
@@ -1,4 +1,4 @@
-CONSOLE ERROR: line 9: Uncaught SyntaxError: Expected () to start arrow function, but got '}' instead of '=>'
+CONSOLE ERROR: line 9: Uncaught SyntaxError: Unexpected token )
 Tests that pause on exception in internal script does not crash.

 Script source was shown.

Original issue's description:
> Parse arrow functions at proper precedence level
>
> BUG=v8:4211
> LOG=Y
> R=rossberg@chromium.org
>
> Committed: https://crrev.com/9271b0ccf9ddb217deb1f0b9ef9b59b64dc40214
> Cr-Commit-Position: refs/heads/master@{#30298}

TBR=rossberg@chromium.org,mstarzinger@chromium.org,fennyfanny655@gmail.com,machenbach@chromium.org,wingo@igalia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4211

Review URL: https://codereview.chromium.org/1315503002

Cr-Commit-Position: refs/heads/master@{#30318}