ninjabackend: avoid lambdas

The lambda in NinjaBuildElement.write is quite expensive, totalling 0.3s
just to do a couple function calls.  Since it is used just once, simply
inline it.

On a QEMU build, the total time spent in write from this series goes from
5.321s to 3.238s, though part of it can be attributed to previous patches.

mesonbuild/backend/ninjabackend.py

@@ -386,10 +386,9 @@ class NinjaBuildElement:
             newelems = []
             for i in elems:
                 if not should_quote or i == '&&': # Hackety hack hack
-                    quoter = ninja_quote
+                    newelems.append(ninja_quote(i))
                 else:
-                    quoter = lambda x: ninja_quote(qf(x))
-                newelems.append(quoter(i))
+                    newelems.append(ninja_quote(qf(i)))
             line += ' '.join(newelems)
             line += '\n'
             outfile.write(line)