Fix warnings reported by -Wshadow: Part3: test/ directory

Cherry-picked from aomedia/master: be029580

Change-Id: I3bab28488388f92f2db20e6af8fc9cf2d7f26015
diff --git a/test/partial_idct_test.cc b/test/partial_idct_test.cc
index c18f48b..7eedfaf 100644
--- a/test/partial_idct_test.cc
+++ b/test/partial_idct_test.cc
@@ -55,7 +55,6 @@
 };
 
 TEST_P(PartialIDctTest, RunQuantCheck) {
-  ACMRandom rnd(ACMRandom::DeterministicSeed());
   int size;
   switch (tx_size_) {
     case TX_4X4: size = 4; break;
@@ -76,7 +75,7 @@
   DECLARE_ALIGNED(16, tran_low_t, output_ref_block[kMaxNumCoeffs]);
 
   int max_error = 0;
-  for (int i = 0; i < count_test_block; ++i) {
+  for (int m = 0; m < count_test_block; ++m) {
     // clear out destination buffer
     memset(dst1, 0, sizeof(*dst1) * block_size);
     memset(dst2, 0, sizeof(*dst2) * block_size);
@@ -85,11 +84,11 @@
 
     ACMRandom rnd(ACMRandom::DeterministicSeed());
 
-    for (int i = 0; i < count_test_block; ++i) {
+    for (int n = 0; n < count_test_block; ++n) {
       // Initialize a test block with input range [-255, 255].
-      if (i == 0) {
+      if (n == 0) {
         for (int j = 0; j < block_size; ++j) input_extreme_block[j] = 255;
-      } else if (i == 1) {
+      } else if (n == 1) {
         for (int j = 0; j < block_size; ++j) input_extreme_block[j] = -255;
       } else {
         for (int j = 0; j < block_size; ++j) {