lib: clean up usage of threw

Use try/catch to instead of threw.

PR-URL: #10534
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

Author: JacksonTian

lib/internal/bootstrap_node.js

@@ -430,20 +430,14 @@
   }
 
   function tryGetCwd(path) {
-    var threw = true;
-    var cwd;
     try {
-      cwd = process.cwd();
-      threw = false;
-    } finally {
-      if (threw) {
-        // getcwd(3) can fail if the current working directory has been deleted.
-        // Fall back to the directory name of the (absolute) executable path.
-        // It's not really correct but what are the alternatives?
-        return path.dirname(process.execPath);
-      }
+      return process.cwd();
+    } catch (ex) {
+      // getcwd(3) can fail if the current working directory has been deleted.
+      // Fall back to the directory name of the (absolute) executable path.
+      // It's not really correct but what are the alternatives?
+      return path.dirname(process.execPath);
     }
-    return cwd;
   }
 
   function evalScript(name) {