Mark the precompilation tests as slow.

tests/standalone/standalone.status

 # Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # WARNING:
 # Tests using the multitest feature where failure is expected should *also* be
 # listed in tests/lib/analyzer/analyze_tests.status without the "standalone"
 # prefix.
 
 package/invalid_uri_test: Fail, OK # CompileTimeErrors intentionally
@@ skipping 98 matching lines @@
 issue14236_test: Skip # dart2js does not deal with Script snapshots.
 unboxed_int_converter_test: Skip
 pair_location_remapping_test: Skip
 precompilation_test: Skip # Standalone only test.
 precompilation_dart2js_test: Skip # Standalone only test.
 regress_25335_test: Skip # Int64List not supported.
 
 [ $compiler == dart2js && $cps_ir && $checked ]
 *: Skip # `assert` not implemented
 
-[ ($runtime == vm || $runtime == dart_product) && $mode == debug ]
+[ ($runtime == vm || $runtime == dart_product) ]
 precompilation_dart2js_test: Pass, Slow
 
 [ ($runtime == vm || $runtime == dart_product) && $arch == ia32 ]
 precompilation_test: SkipByDesign # Not expected to pass on ia32.
 precompilation_dart2js_test: SkipByDesign # Not expected to pass on ia32.
 
 [ ($runtime == vm || $runtime == dart_product) && ($arch == mips || $arch == arm || $arch == arm64) ]
 precompilation_test: SkipSlow
 precompilation_dart2js_test: SkipSlow
 
@@ skipping 166 matching lines @@
 # Following tests are skipped on dart_product as package mapping is not supported.
 [ $runtime == dart_product ]
 package/scenarios/packages_file_strange_formatting/mixed_line_ends_test: Skip
 package/scenarios/packages_file_strange_formatting/empty_lines_test: Skip
 package/scenarios/invalid/invalid_utf8_test: Skip
 package/scenarios/invalid/same_package_twice_test: Skip
 package/scenarios/invalid/non_existent_packages_file_test: Skip
 package/scenarios/empty_packages_file/empty_packages_file_noimports_test: Skip
 package/scenarios/packages_option_only/packages_option_only_noimports_test: Skip
 package/scenarios/packages_option_only/packages_option_only_test: Skip