Don't set kernel.console to null

When we do, the entire VM runs very slowly.

Bug: 219743539
Bug: 220824234
Test: Time compos_verify
Change-Id: I660e5a98a63a2cce9ca58eb83d58101111033a59
diff --git a/microdroid/bootconfig.normal b/microdroid/bootconfig.normal
index 708d64b..ea83287 100644
--- a/microdroid/bootconfig.normal
+++ b/microdroid/bootconfig.normal
@@ -7,7 +7,8 @@
 # Console output is not redirect to the host-side.
 # TODO(b/219743539) This doesn't successfully disable the console
 kernel.printk.devkmsg=off
-kernel.console=null
+# TODO(b/219743539) Setting this to null makes everything slow
+kernel.console=hvc0
 
 # ADB is not enabled.
 androidboot.adb.enabled=0