RFR: 8265469: Allow to build media and webkit for Linux-AArch64 [v2]

[Johan Vos]

> Changes that allow to build linux configuration on Linux AArch64
> This PR introduces an `IS_AARCH64` parameter in build.gradle.
> This PR already contains the change from PR #465 so if this one gets integrated, that change needs to removed from this PR.

Johan Vos has updated the pull request incrementally with one additional commit since the last revision:

  remove classifier as per reviewer comment

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/467/files
  - new: https://git.openjdk.java.net/jfx/pull/467/files/e67b13cf..9ace50ce

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jfx&pr=467&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jfx&pr=467&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/467.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/467/head:pull/467

PR: https://git.openjdk.java.net/jfx/pull/467