Say kNumDalvikInstructions when appropriate.

In particular, use it instead of just saying 256, and similarly for
255. The number of opcodes will be changing soon.

Change-Id: Icc77120c2673968dddd6b4003f717245d46e4159
diff --git a/vm/compiler/codegen/arm/CodegenCommon.c b/vm/compiler/codegen/arm/CodegenCommon.c
index ee5d9f5..d14dd06 100644
--- a/vm/compiler/codegen/arm/CodegenCommon.c
+++ b/vm/compiler/codegen/arm/CodegenCommon.c
@@ -30,7 +30,7 @@
 static intptr_t templateEntryOffsets[TEMPLATE_LAST_MARK];
 
 /* Track exercised opcodes */
-static int opcodeCoverage[256];
+static int opcodeCoverage[kNumDalvikInstructions];
 
 static void setMemRefType(ArmLIR *lir, bool isLoad, int memType)
 {
diff --git a/vm/compiler/codegen/arm/CodegenDriver.c b/vm/compiler/codegen/arm/CodegenDriver.c
index 8e1d9a2..b52420f 100644
--- a/vm/compiler/codegen/arm/CodegenDriver.c
+++ b/vm/compiler/codegen/arm/CodegenDriver.c
@@ -4383,13 +4383,13 @@
 
     streak = i = 0;
     buf[0] = 0;
-    while (opcodeCoverage[i] == 0 && i < 256) {
+    while (opcodeCoverage[i] == 0 && i < kNumDalvikInstructions) {
         i++;
     }
-    if (i == 256) {
+    if (i == kNumDalvikInstructions) {
         return;
     }
-    for (start = i++, streak = 1; i < 256; i++) {
+    for (start = i++, streak = 1; i < kNumDalvikInstructions; i++) {
         if (opcodeCoverage[i]) {
             streak++;
         } else {
@@ -4399,10 +4399,10 @@
                 sprintf(buf+strlen(buf), "%x-%x,", start, start + streak - 1);
             }
             streak = 0;
-            while (opcodeCoverage[i] == 0 && i < 256) {
+            while (opcodeCoverage[i] == 0 && i < kNumDalvikInstructions) {
                 i++;
             }
-            if (i < 256) {
+            if (i < kNumDalvikInstructions) {
                 streak = 1;
                 start = i;
             }