patch 8.2.3442: Vim9: || and && are not handled at compile time

Problem:    Vim9: || and && are not handled at compile time when possible.
Solution:   When using constants generate fewer instructions.
diff --git a/src/vim9.h b/src/vim9.h
index 66fc6cc..cffa71b 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -221,6 +221,7 @@
 
 typedef enum {
     JUMP_ALWAYS,
+    JUMP_NEVER,
     JUMP_IF_FALSE,		// pop and jump if false
     JUMP_AND_KEEP_IF_TRUE,	// jump if top of stack is truthy, drop if not
     JUMP_AND_KEEP_IF_FALSE,	// jump if top of stack is falsy, drop if not