[mb] Build linux libFuzzers with is_lsan=true.

tools/mb/mb_config.pyl

Index: tools/mb/mb_config.pyl
diff --git a/tools/mb/mb_config.pyl b/tools/mb/mb_config.pyl
index 5e0d52ce5d9e8fea228c135c33bd2ec17739aa6a..ea430dd433faed6f72dd9c3cb6c61e710e579a0c 100644
--- a/tools/mb/mb_config.pyl
+++ b/tools/mb/mb_config.pyl
@@ -1122,7 +1122,7 @@
     ],
 
     'debug_libfuzzer_asan': [
-      'debug', 'libfuzzer', 'asan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
+      'debug', 'libfuzzer', 'asan', 'lsan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
     ],
 
     'drmemory_shared_release': [
@@ -1357,11 +1357,11 @@
      ],
 
     'release_libfuzzer_asan': [
-      'release', 'libfuzzer', 'asan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
+      'release', 'libfuzzer', 'asan', 'lsan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
     ],
 
     'release_libfuzzer_asan_clang_tot': [
-      'clang_tot', 'release', 'libfuzzer', 'asan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
+      'clang_tot', 'release', 'libfuzzer', 'asan', 'lsan', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl',
     ],
 
     'release_libfuzzer_mac_asan': [