Enable leak detection on linux-i686 by default

[fjricci]

Summary

This is already assumed by the test suite, and by
asan_flags.cc.

[fjricci]

As discussed in D31430, looks like 32-bit linux leak detection should be enabled by default.

[m.ostapenko]

Looks good, thank you.

lib/sanitizer_common/sanitizer_flags.inc

COMMON_FLAG(
     "append executable name to logs (as in \"log_path.exe_name.pid\").")
 COMMON_FLAG(
     bool, log_to_syslog, SANITIZER_ANDROID || SANITIZER_MAC,
     "Write all sanitizer output to syslog in addition to other means of "
     "logging.")
 COMMON_FLAG(
     int, verbosity, 0,
     "Verbosity level (0 - silent, 1 - a bit of output, 2+ - more output).")
-COMMON_FLAG(bool, detect_leaks, SANITIZER_WORDSIZE == 64,
-            "Enable memory leak detection.")
+COMMON_FLAG(bool, detect_leaks, true, "Enable memory leak detection.")
 COMMON_FLAG(
     bool, leak_check_at_exit, true,
     "Invoke leak checking in an atexit handler. Has no effect if "
     "detect_leaks=false, or if __lsan_do_leak_check() is called before the "
     "handler has a chance to run.")
 COMMON_FLAG(bool, allocator_may_return_null, false,
             "If false, the allocator will crash instead of returning 0 on "
             "out-of-memory.")