Bug 1618620 - Convert run_spidermonkey_checks.py to py3; r=firefox-build-system-reviewers,rstewart

Differential Revision: https://phabricator.services.mozilla.com/D64625

--HG--
extra : moz-landing-system : lando

config/check_spidermonkey_style.py

@@ -320,7 +320,7 @@ def check_style(enable_fixup):
            file_kind == FileKind.H or file_kind == FileKind.INL_H:
             included_h_inclnames = set()    # type: set(inclname)
 
-            with open(filename) as f:
+            with open(filename, encoding='utf-8') as f:
                 code = read_file(f)
 
             if enable_fixup:

js/src/build/moz.build

@@ -85,7 +85,6 @@ DIST_INSTALL = True
 # running the script for no-op builds.
 GeneratedFile(
     'spidermonkey_checks', script='/config/run_spidermonkey_checks.py',
-    py2=True,
     inputs=[
         '!%sjs_static.%s' % (CONFIG['LIB_PREFIX'], CONFIG['LIB_SUFFIX']),
         '/config/check_spidermonkey_style.py',

js/src/vm/jsopcode.py

@@ -200,7 +200,7 @@ def get_opcodes(dir):
     opcodes = dict()
     index = []
 
-    with open('{dir}/js/src/vm/Opcodes.h'.format(dir=dir), 'r') as f:
+    with open('{dir}/js/src/vm/Opcodes.h'.format(dir=dir), 'r', encoding='utf-8') as f:
         data = f.read()
 
     comment_info = None