RFR: 8257897: Fix webkit build for XCode 12

[Kevin Rushforth]

On Tue, 8 Dec 2020 17:29:56 GMT, Arun Joseph <ajoseph at openjdk.org> wrote:

> The WebKit build fails with recent Xcode 12.
> 
> Bug: `getVTablePointer()` should return a const void*
> 
> Fix: Use const void* and remove dependency on JavaVM.framework in Xcode
> Upstream fix: https://bugs.webkit.org/show_bug.cgi?id=207871
> 
> Test: Build webkit with the Xcode 12 compiler with and without this fix. It should fail without the fix and build with the fix.

Looks good. I tested it with both Xcode 11.3.1 and Xcode 12.2.

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Marked as reviewed by kcr (Lead).

PR: https://git.openjdk.java.net/jfx/pull/365