Refactor the memory slot check logic to improve readability

Bug: 293811969
Test: TH
Change-Id: I77e91960e46aeb2c205d772e0f3e6129b97dd5b4

src/android/net/apf/ApfGenerator.java

diff --git a/src/android/net/apf/ApfGenerator.java b/src/android/net/apf/ApfGenerator.java
index 28234b1..12b09a8 100644
--- a/src/android/net/apf/ApfGenerator.java
+++ b/src/android/net/apf/ApfGenerator.java
@@ -285,7 +285,7 @@
         Instruction(ExtendedOpcodes extendedOpcodes, int slot, Register register)
                 throws IllegalInstructionException {
             this(Opcodes.EXT, register);
-            if (slot < 0 || slot > (MEMORY_SLOTS - 1)) {
+            if (slot < 0 || slot >= MEMORY_SLOTS) {
                 throw new IllegalInstructionException("illegal memory slot number: " + slot);
             }
             addUnsignedIndeterminate(extendedOpcodes.value + slot);