Fixes typo in attributes for trace benchmarks. (#1838)

Author: dinooliva

benchmarks/src/jmh/java/io/opencensus/benchmarks/trace/BasicDataBenchmark.java

@@ -65,7 +65,7 @@ public void setup() {
       attributeKeys = new String[size];
       attributeMap = new HashMap<>(size);
       for (int i = 0; i < size; i++) {
-        attributeKeys[i] = ATTRIBUTE_KEY + "-i";
+        attributeKeys[i] = ATTRIBUTE_KEY + "-" + i;
         attributeMap.put(attributeKeys[i], attributeValues[i]);
       }
     }

benchmarks/src/jmh/java/io/opencensus/benchmarks/trace/SpanOperationsBenchmark.java

@@ -214,7 +214,7 @@ public Span addLink(Data data) {
   private static AttributeValue[] createAttributeValues(int size) {
     AttributeValue[] attributeValues = new AttributeValue[size];
     for (int i = 0; i < size; i++) {
-      attributeValues[i] = AttributeValue.stringAttributeValue(ATTRIBUTE_VALUE + "-i");
+      attributeValues[i] = AttributeValue.stringAttributeValue(ATTRIBUTE_VALUE + "-" + i);
     }
     return attributeValues;
   }