Bump minimum version of macOS for x64 to 11.0 (matching aarch64)

As proposed in this openjfx-dev message [1], we need to bump the version of the macOS to something newer than 10.12.

Apple hasn't supported 10.12 in several years, and there is an ongoing (and increasing) cost to our code base to keep building and targeting a system that old. Additionally, Xcode 14 no longer supports targeting 10.12, and we will need to update to Xcode 14 soon. It is also a little awkward to have a different minimum version for the two different chip architectures.

As a result, we should change the minimum version for Mac / x64 to be macOS 11.0, matching both the currently oldest version of macOS supported by Apple, and also unifying the minimum for the two chip architectures.

We could do that in one step or two steps as follows:

Option 1:

JavaFX 21: Bump the minimum (for Intel platforms) to macOS 11

Option 2:

JavaFX 21: Bump the minimum (for Intel platforms) to macOS 10.14
JavaFX 22: Bump the minimum (for Intel platforms) to macOS 11


I propose Option 1, and plan to send a PR out in the next day or two.

[1] https://mail.openjdk.org/pipermail/openjfx-dev/2023-May/040392.html