Don't use abort_on_error for lsan darwin test suite

[fjricci]

Summary

This option is disabled by our other test suites, and will cause
failures when unit tests abort instead of failing with an error code.
Will also prevent the test suite from being too slow.

[kubamracek]

Can this be two separate changes, 1) NFC for the LSAN_OPTIONS => %env_lsan_opts conversion, and 2) the Darwin change to add abort_on_error=0?

[fjricci]

Yeah, I can do that.

[fjricci]

Split out abort_on_error and NFC

test/lsan/lit.common.cfg

elif lsan_lit_test_mode == "AddressSanitizer":
   lsan_cflags = ["-fsanitize=address"]
   config.available_features.add('asan')
 else:
   lit_config.fatal("Unknown LSan test mode: %r" % lsan_lit_test_mode)
 config.name += config.name_suffix
 
 # Platform-specific default LSAN_OPTIONS for lit tests.
 default_lsan_opts = ''
+if config.host_os == 'Darwin':
+  # On Darwin, we default to `abort_on_error=1`, which would make tests run
+  # much slower. Let's override this and run lit tests with 'abort_on_error=0'.
+  # Also, make sure we do not overwhelm the syslog while testing.
+  default_lsan_opts = 'abort_on_error=0'
+  default_lsan_opts += ':log_to_syslog=0'
+
 if default_lsan_opts:
   config.environment['LSAN_OPTIONS'] = default_lsan_opts
   default_lsan_opts += ':'
 config.substitutions.append(('%env_lsan_opts=',
                              'env LSAN_OPTIONS=' + default_lsan_opts))
 
 if lit.util.which('strace'):
   config.available_features.add('strace')