The escaped double quote is needed for calling CSA macros that expect
const char* (so the double quotes are preserved).

Example:

type MethodName;
const kProtoSort: MethodName = '\"%TypedArray%.prototype.sort\"';
extern macro ValidateTypedArray(Context, Object, MethodName): JSTypedArray;

R=danno@chromium.org

Bug: v8:7382
Change-Id: Ida554f7d2638fda2c9e1ace9975c3744b5d84050
Reviewed-on: https://chromium-review.googlesource.com/1016400Reviewed-by: Daniel Clifford <danno@chromium.org>
Commit-Queue: Simon Zünd <szuend@google.com>
Cr-Commit-Position: refs/heads/master@{#52666}