ReFrame silently ignores wrong test files

[vkarak]

The following wrong test file is simply ignored by ReFrame:

import reframe as rfm
import reframe.utility.sanity as sn


@rfm.simple_test
class SedTest(rfm.CompileOnlyTest):
    def __init__(self):
        super().__init__()
        self.valid_systems = ['*']
        self.valid_prog_environs = ['*']
        self.sourcesdir = 'https://github.com/mirror/sed'
        self.prebuild_cmd = ['autoreconf -vfi']
        self.build_system = 'Autotools'
        self.build_system.builddir = 'build'
        self.sanity_patterns = sn.assert_found('.*', self.stdout)

Command line: ./bin/reframe -C config/tresa.py -c ../misc/rfm-checks/sed.py -l
Reframe version: 2.14-dev2
Launched by user: karakasv
Launched on host: tresa.local
Reframe paths
=============
    Check prefix      :
    Check search path : '../misc/rfm-checks/sed.py'
    Stage dir prefix     : /Users/karakasv/Repositories/reframe/stage/
    Output dir prefix    : /Users/karakasv/Repositories/reframe/output/
    Perf. logging prefix : /Users/karakasv/Repositories/reframe/perflogs
List of matched checks
======================
Found 0 check(s).

The problem in this file is that the base class for compile-only tests is CompileOnlyRegressionTest not CompileOnlyTest. I think it has something to do with the initial parsing of the source files.