feat: add test case for ignoring whitespace

cases/2.out

@@ -1,3 +1,4 @@
+3072
 234890234
 342342
 1234234

cases/3.in

@@ -0,0 +1 @@
+1024 2048

cases/3.out

@@ -0,0 +1 @@
+3072  

cases/4.in

@@ -0,0 +1 @@
+1024 2048

cases/4.out

@@ -0,0 +1 @@
+3072  

conf.toml

@@ -50,6 +50,12 @@ src = "./cases/1.in"
 [[stages.executor.with.cases]]
 [stages.executor.with.cases.stdin]
 src = "./cases/2.in"
+[[stages.executor.with.cases]]
+[stages.executor.with.cases.stdin]
+src = "./cases/3.in"
+[[stages.executor.with.cases]]
+[stages.executor.with.cases.stdin]
+src = "./cases/4.in"
 [stages.parser]
 name = "diff"
 [[stages.parser.with.cases]]
@@ -58,3 +64,11 @@ stdoutPath = "./cases/1.out"
 [[stages.parser.with.cases]]
 score = 100
 stdoutPath = "./cases/2.out"
+[[stages.parser.with.cases]]
+score = 100
+stdoutPath = "./cases/3.out"
+ignoreWhitespace=true
+[[stages.parser.with.cases]]
+score = 100
+stdoutPath = "./cases/4.out"
+ignoreWhitespace=false