lib: do not crash using workers with disabled shared array buffers

This allows the repl to function normally while using the
`--no-harmony-sharedarraybuffer` V8 flag.

Fixes: nodejs#39717

Signed-off-by: Ruben Bridgewater <ruben@bridgewater.de>

lib/internal/bootstrap/switches/does_own_process_state.js

@@ -6,7 +6,7 @@ const rawMethods = internalBinding('process_methods');
 process.abort = rawMethods.abort;
 process.umask = wrappedUmask;
 process.chdir = wrappedChdir;
-process.cwd = wrappedCwd;
+process.cwd = typeof SharedArrayBuffer === 'undefined' ? rawMethods.cwd : wrappedCwd;
 
 if (credentials.implementsPosixCredentials) {
   const wrapped = wrapPosixCredentialSetters(credentials);

lib/internal/worker.js

@@ -90,7 +90,7 @@ let cwdCounter;
 
 const environmentData = new SafeMap();
 
-if (isMainThread) {
+if (isMainThread && typeof SharedArrayBuffer !== 'undefined') {
   cwdCounter = new Uint32Array(new SharedArrayBuffer(4));
   const originalChdir = process.chdir;
   process.chdir = function(path) {