Do not disable interrupts on abort

Allows panic messages to be printed fully into serial console

src/runtime/runtime_cortexm_abort.go

@@ -7,9 +7,6 @@ import (
 )
 
 func abort() {
-	// disable all interrupts
-	arm.DisableInterrupts()
-
 	// lock up forever
 	for {
 		arm.Asm("wfi")