v8: do not test v8 with -Werror

PR-URL: nodejs#12875
Reviewed-By: James M Snell <[email protected]>

Author: addaleax

deps/v8/gypfiles/standalone.gypi

@@ -190,7 +190,7 @@
     'host_clang%': '<(host_clang)',
     'target_arch%': '<(target_arch)',
     'v8_target_arch%': '<(v8_target_arch)',
-    'werror%': '-Werror',
+    'werror%': '',
     'use_goma%': '<(use_goma)',
     'gomadir%': '<(gomadir)',
     'asan%': '<(asan)',

deps/v8/gypfiles/toolchain.gypi

@@ -81,7 +81,7 @@
     'v8_toolset_for_shell%': 'target',
 
     'host_os%': '<(OS)',
-    'werror%': '-Werror',
+    'werror%': '',
     # For a shared library build, results in "libv8-<(soname_version).so".
     'soname_version%': '',