PSI2IR / FIR2IR: do not create temporaries for adapted references

Arguments to function references behave the same as arguments to
function calls and should be evaluated once regardless, so the temporary
is unnecessary.

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -529,12 +529,6 @@ val IrDeclaration.isFileClass: Boolean
 val IrValueDeclaration.isImmutable: Boolean
     get() = this is IrValueParameter || this is IrVariable && !isVar
 
-fun IrExpression.isSafeToUseWithoutCopying() =
-    this is IrGetObjectValue ||
-            this is IrGetEnumValue ||
-            this is IrConst<*> ||
-            this is IrGetValue && symbol.isBound && symbol.owner.isImmutable
-
 val IrStatementOrigin?.isLambda: Boolean
     get() = this == IrStatementOrigin.LAMBDA || this == IrStatementOrigin.ANONYMOUS_FUNCTION