Small fixes suggested by SpotBugs

Author: eregon

src/main/java/org/truffleruby/core/rope/RopeConstants.java

@@ -30,7 +30,7 @@ public class RopeConstants {
     public static final LeafRope[] UTF8_SINGLE_BYTE_ROPES = new LeafRope[256];
     public static final LeafRope[] US_ASCII_SINGLE_BYTE_ROPES = new LeafRope[256];
     public static final LeafRope[] ASCII_8BIT_SINGLE_BYTE_ROPES = new LeafRope[256];
-    public static final Map<String, LeafRope> ROPE_CONSTANTS = new HashMap<>();
+    static final Map<String, LeafRope> ROPE_CONSTANTS = new HashMap<>();
 
     static {
         for (int i = 0; i < 128; i++) {

src/main/java/org/truffleruby/parser/scope/StaticScope.java

@@ -214,6 +214,7 @@ public int exists(String name) {
         return findVariableName(name);
     }
 
+    @SuppressFBWarnings("ES")
     private int findVariableName(String name) {
         assert name == name.intern() : name;
         for (int i = 0; i < variableNames.length; i++) {
@@ -327,6 +328,7 @@ public long getCommandArgumentStack() {
         return commandArgumentStack;
     }
 
+    @SuppressFBWarnings("ES")
     private void growVariableNames(String name) {
         assert name == name.intern() : name;
         String[] newVariableNames = new String[variableNames.length + 1];