Don't spin up the ART runtime in art_standalone_dex2oat_cts_tests.

It was mistakenly based on CommonRuntimeTest, which starts a runtime
through unstable APIs. The test should only run dex2oat with minimal
arguments to make --force-palette-compilation-hooks work.

Some refactoring in Dex2oatEnvironmentTest and CommonArtTest to
separate out the scratch directory creation code.

Test: atest Dex2oatCtsTest
  Check with temporary logging in
  system/libartpalette/palette_android_partner.cc that
  PaletteNotify(Start|End)Dex2oatCompilation still gets called.
Bug: 253937792
Bug: 255895245
Change-Id: Ieaea0faeef9571c0a269d565acd105d0f74f3d13
(cherry picked from commit 2847729bd291b225f0f289242ee10020ca69eee2)
Merged-In: Ieaea0faeef9571c0a269d565acd105d0f74f3d13
3 files changed