Remove "is_component_build=true" from libFuzzer UBSan build.

There are some build issues with fuzz targets for blink. Also, we've decided
to postpone the switch towards component build because of potential issues
with sancov-based generation of code coverage stats and reports.

TBR=dpranke@chromium.org, ochang@chromium.org

Bug: 768918, 701825
Change-Id: Iea97a0db39796e142a420821f05726137addba78
Reviewed-on: https://chromium-review.googlesource.com/691212
Commit-Queue: Max Moroz <mmoroz@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Max Moroz <mmoroz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#505272}

tools/mb/mb_config.pyl

@@ -1533,7 +1533,7 @@
     ],
 
     'release_libfuzzer_ubsan': [
-      'release', 'libfuzzer', 'ubsan_security', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing', 'shared',
+      'release', 'libfuzzer', 'ubsan_security', 'chromeos_codecs', 'pdf_xfa', 'disable_nacl', 'optimize_for_fuzzing',
     ],
 
     'release_trybot': [