test: remove duplicate NaN test cases in normal mean

PR-URL: #9588
Closes: #9567

Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>
Signed-off-by: Suyash Pathak <suyashp271@gmail.com>

Author: SuYaSh-PaThAk04

lib/node_modules/@stdlib/stats/base/dists/cosine/mean/test/test.js

@@ -57,9 +57,6 @@ tape( 'if provided a nonpositive `s`, the function returns `NaN`', function test
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/gumbel/mean/test/test.js

@@ -59,9 +59,6 @@ tape( 'if provided a nonpositive `beta`, the function returns `NaN`', function t
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/gumbel/mean/test/test.native.js

@@ -68,9 +68,6 @@ tape( 'if provided a nonpositive `beta`, the function returns `NaN`', opts, func
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/laplace/mean/test/test.js

@@ -57,9 +57,6 @@ tape( 'if provided a nonpositive `b`, the function returns `NaN`', function test
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/laplace/mean/test/test.native.js

@@ -68,9 +68,6 @@ tape( 'if provided a nonpositive `b`, the function returns `NaN`', opts, functio
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/levy/mean/test/test.js

@@ -53,9 +53,6 @@ tape( 'if provided a nonpositive `c`, the function returns `NaN`', function test
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/levy/mean/test/test.native.js

@@ -62,9 +62,6 @@ tape( 'if provided a nonpositive `c`, the function returns `NaN`', opts, functio
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/logistic/mean/test/test.js

@@ -59,9 +59,6 @@ tape( 'if provided a nonpositive `s`, the function returns `NaN`', function test
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/lognormal/mean/test/test.js

@@ -59,9 +59,6 @@ tape( 'if provided a nonpositive `sigma`, the function returns `NaN`', function
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 

lib/node_modules/@stdlib/stats/base/dists/lognormal/mean/test/test.native.js

@@ -68,9 +68,6 @@ tape( 'if provided a nonpositive `sigma`, the function returns `NaN`', opts, fun
 	y = mean( 2.0, -1.0 );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );
 
-	y = mean( 2.0, -1.0 );
-	t.strictEqual( isnan( y ), true, 'returns expected value' );
-
 	y = mean( 1.0, NINF );
 	t.strictEqual( isnan( y ), true, 'returns expected value' );