fix whitespace issues

test/filecheck/hello-world.asm

@@ -12,4 +12,4 @@ msg:    .ascii "Hello world\n"
         scall
 
 // CHECK: Hello world
-// CHECK: [CPU] Program exited with code 0
+// CHECK: [CPU] Program exited with code 0

test/filecheck/lit.cfg

@@ -7,4 +7,3 @@ xdsl_src = os.path.dirname(os.path.dirname(config.test_source_root))
 config.name = "riscemu"
 config.test_format = lit.formats.ShTest(preamble_commands=[f"cd {xdsl_src}"])
 config.suffixes = ['.asm']
-