[LSAN][HWASAN] Turn on leak sanitizer in HWASAN for Linux

[vitalybuka]

compiler-rt/lib/hwasan/hwasan.cpp

89–91

Maybe comment that as now it's tested on Linux, any other platforms are welcome to validate and enable the thing.

[vitalybuka]

https://lab.llvm.org/buildbot/#/builders/169/builds/17791

[kstoimenov]

This was relanded as b33437c969f3.

compiler-rt/lib/hwasan/hwasan.cpp

SetCommonFlagsDefaults();
     // FIXME: test and enable.
     cf.check_printf = false;
     cf.intercept_tls_get_addr = true;
     cf.exitcode = 99;
     // 8 shadow pages ~512kB, small enough to cover common stack sizes.
     cf.clear_shadow_mmap_threshold = 4096 * (SANITIZER_ANDROID ? 2 : 8);
     // Sigtrap is used in error reporting.
     cf.handle_sigtrap = kHandleSignalExclusive;
-    // FIXME: enable once all false positives have been fixed.
-    cf.detect_leaks = false;
+    // For now only tested on Linux. Other plantforms can be turned on as they
+    // become ready.
+    cf.detect_leaks = cf.detect_leaks && SANITIZER_LINUX && !SANITIZER_ANDROID;
 
 #if SANITIZER_ANDROID
     // Let platform handle other signals. It is better at reporting them then we
     // are.
     cf.handle_segv = kHandleSignalNo;
     cf.handle_sigbus = kHandleSignalNo;
     cf.handle_abort = kHandleSignalNo;
     cf.handle_sigill = kHandleSignalNo;