Poll if process is still alive in Test.py

In some cases this script did not detect properly that the subprocess is already terminated. The "append" loop afterwards caused memory to fill up and the script to fail eventually.

Builds/Test.py

@@ -264,17 +264,20 @@ def shell(cmd, args=(), silent=False):
     count = 0
     # readline returns '' at EOF
     for line in iter(process.stdout.readline, ''):
-        decoded = decodeString(line)
-        lines.append(decoded)
-        if verbose:
-            print(decoded, end='')
-        elif not silent:
-            count += 1
-            if count >= 80:
-                print()
-                count = 0
-            else:
-                print('.', end='')
+        if process.poll() is None:
+            decoded = decodeString(line)
+            lines.append(decoded)
+            if verbose:
+                print(decoded, end='')
+            elif not silent:
+                count += 1
+                if count >= 80:
+                    print()
+                    count = 0
+                else:
+                    print('.', end='')
+        else:
+            break
 
     if not verbose and count:
         print()