bench: refactor random number generation in stats/base/dists/normal

---
type: pre_commit_static_analysis_report
description: Results of running static analysis checks when committing changes.
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    status: passed
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---

Author: pranav-1720

lib/node_modules/@stdlib/stats/base/dists/normal/pdf/benchmark/benchmark.js

@@ -51,7 +51,7 @@ bench( pkg, function benchmark( b ) {
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		y = pdf( x[ i % 100 ], mu[ i % 100 ], sigma[ i % 100 ] );
+		y = pdf( x[ i % len ], mu[ i % len ], sigma[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}

lib/node_modules/@stdlib/stats/base/dists/normal/quantile/benchmark/benchmark.js

@@ -51,7 +51,7 @@ bench( pkg, function benchmark( b ) {
 
 	b.tic();
 	for ( i = 0; i < b.iterations; i++ ) {
-		y = quantile( p[ i % 100 ], mu[ i % 100 ], sigma[ i % 100 ] );
+		y = quantile( p[ i % len ], mu[ i % len ], sigma[ i % len ] );
 		if ( isnan( y ) ) {
 			b.fail( 'should not return NaN' );
 		}