Remove directives that have no effect from bytecode text tests

All bytecode text tests are run with stdlib in the classpath and only
for JVM backend, therefore directives WITH_RUNTIME, TARGET_BACKEND,
IGNORE_BACKEND are not needed

compiler/testData/codegen/bytecodeText/nullCheckOptimization/ifUnitEqualsNull.kt

@@ -1,5 +1,3 @@
-// WITH_RUNTIME
-
 fun test1() {
     val a = Unit
 
@@ -15,4 +13,4 @@ fun test1() {
 // 0 IFNULL
 // 0 IFNONNULL
 // 1 X1
-// 0 X2
+// 0 X2