[tests] Cleanup tests that use assertOptimized()/assertUnoptimized().

test/mjsunit/regress/regress-347914.js

Index: test/mjsunit/regress/regress-347914.js
diff --git a/test/mjsunit/regress/regress-347914.js b/test/mjsunit/regress/regress-347914.js
index bc4dcd7f743505e31c745a43792b5bafdd232e83..ec693ee92c13d1136a79dfd281dbdbbeff4a2227 100644
--- a/test/mjsunit/regress/regress-347914.js
+++ b/test/mjsunit/regress/regress-347914.js
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax --debug-code --gc-interval=201 --verify-heap --max-inlined-source-size=999999 --max-inlined-nodes=999999 --max-inlined-nodes-cumulative=999999
+// Flags: --crankshaft --no-always-opt
 
 // Begin stripped down and modified version of mjsunit.js for easy minimization in CF.
 function MjsUnitAssertionError(message) {}