bios-tables-test: fix ASL normalization false positive

My version of IASL (from RHEL7) puts two newlines between the head comment
and the DefinitionBlock property.  Kill all newlines after the comment,
so that normalize_asl works properly.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: NLaszlo Ersek <lersek@redhat.com>

tests/bios-tables-test.c

@@ -487,7 +487,11 @@ static GString *normalize_asl(gchar *asl_code)
     /* strip comments (different generation days) */
     comment = g_strstr_len(asl->str, asl->len, COMMENT_END);
     if (comment) {
-        asl = g_string_erase(asl, 0, comment + sizeof(COMMENT_END) - asl->str);
+        comment += strlen(COMMENT_END);
+        while (*comment == '\n') {
+            comment++;
+        }
+        asl = g_string_erase(asl, 0, comment - asl->str);
     }
 
     /* strip def block name (it has file path in it) */