Stop using process.umask() (#28)

It's deprecated in the latest Node.js due to being insecure and
it's not necessary to use it in the first place because the umask
is automatically applied when creating the directory.

Refs: nodejs/node#32321
Refs: isaacs/node-mkdirp#22

v8-compile-cache.js

@@ -272,7 +272,7 @@ class NativeCompileCache {
 //------------------------------------------------------------------------------
 
 function mkdirpSync(p_) {
-  _mkdirpSync(path.resolve(p_), parseInt('0777', 8) & ~process.umask());
+  _mkdirpSync(path.resolve(p_), 0o777);
 }
 
 function _mkdirpSync(p, mode) {