RFR: 8264219: tools/scripts/build.ps1 is out of date and no longer works

[Kevin Rushforth]

As noted in PR #212 the unused `tools/scripts/build.ps1` script no longer works. This script was added in support of the Appveyor builds in the old `javafxports/openjdk-jfx` sandbox repo, which haven't been used in nearly two years. In its current state, it is more harmful to leave it in, as it is a source of confusion. Since the script is unused, this PR will simply delete it.

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Commit messages:
 - 8264219: tools/scripts/build.ps1 is out of date and no longer works

Changes: https://git.openjdk.java.net/jfx/pull/490/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=490&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8264219
  Stats: 72 lines in 1 file changed: 0 ins; 72 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/490.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/490/head:pull/490

PR: https://git.openjdk.java.net/jfx/pull/490