Fix nonunique test ids in math_testcases.txt.

Author: mdickinson

Lib/test/math_testcases.txt

@@ -551,9 +551,9 @@ log20109 log2 1024.0 -> 10.0
 log20110 log2 2048.0 -> 11.0
 
 log20200 log2 0.5 -> -1.0
-log20200 log2 0.25 -> -2.0
-log20200 log2 0.125 -> -3.0
-log20200 log2 0.0625 -> -4.0
+log20201 log2 0.25 -> -2.0
+log20202 log2 0.125 -> -3.0
+log20203 log2 0.0625 -> -4.0
 
 -- values close to 1.0
 log20300 log2 1.0000000000000002 -> 3.2034265038149171e-16
@@ -573,7 +573,7 @@ log20403 log2 2e-323 -> -1072.0
 log20410 log2 1e-308 -> -1023.1538532253076
 log20411 log2 2.2250738585072014e-308 -> -1022.0
 log20412 log2 4.4501477170144028e-308 -> -1021.0
-log20412 log2 1e-307 -> -1019.8319251304202
+log20413 log2 1e-307 -> -1019.8319251304202
 
 -- huge values
 log20500 log2 1.7976931348623157e+308 -> 1024.0