[infra] Pass TEST_COMPILATION_DIR to Android tests

The whole directory is already copied to the device. This makes
it consistent with tests running on the host and allows us to
access various artefacts (e.g. SO files containing DWARF
information).

Change-Id: I9fe20fdbb48ad5a3742286a84c87f87f580f2c09
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/310600
Reviewed-by: Tess Strickland <sstrickl@google.com>
Commit-Queue: Slava Egorov <vegorov@google.com>

pkg/test_runner/lib/src/process_queue.dart

@@ -666,6 +666,7 @@ class CommandExecutorImpl implements CommandExecutor {
 
     steps.add(() => device.runAdbShellCommand([
           'export LD_LIBRARY_PATH=\$LD_LIBRARY_PATH:$deviceTestDir;'
+              'export TEST_COMPILATION_DIR=$deviceTestDir;'
               '$devicedir/dart_precompiled_runtime',
           '--android-log-to-stderr',
           ...arguments,