IR: call toLowerCase() with root locale

Preventing complexities with Turkish Iı vs. İi.

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/Ir.kt

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.ir.util.ReferenceSymbolTable
 import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
 import org.jetbrains.kotlin.ir.util.getPackageFragment
 import org.jetbrains.kotlin.ir.util.referenceFunction
+import org.jetbrains.kotlin.ir.util.toLowerCase
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.calls.components.isVararg

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/phaser/DumperVerifier.kt

@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.util.dump
 import org.jetbrains.kotlin.ir.util.fqNameWhenAvailable
+import org.jetbrains.kotlin.ir.util.toLowerCase
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
 import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
 import org.jetbrains.kotlin.ir.visitors.acceptVoid

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIntrinsics.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.ir.types.isLong
 import org.jetbrains.kotlin.ir.util.constructors
 import org.jetbrains.kotlin.ir.util.findDeclaration
 import org.jetbrains.kotlin.ir.util.kotlinPackageFqn
+import org.jetbrains.kotlin.ir.util.toLowerCase
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi2ir.findSingleFunction

compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ast/WasmAstToWat.kt

@@ -5,6 +5,8 @@
 
 package org.jetbrains.kotlin.backend.wasm.ast
 
+import org.jetbrains.kotlin.ir.util.toLowerCase
+
 // TODO: Abstract out S-expression part of dumping?
 
 fun WasmInstruction.toWat(ident: String = ""): String =

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

@@ -26,6 +26,7 @@ import org.jetbrains.kotlin.resolve.source.PsiSourceElement
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
 import org.jetbrains.kotlin.utils.DFS
+import java.util.*
 
 /**
  * Binds the arguments explicitly represented in the IR to the parameters of the accessed function.
@@ -614,3 +615,7 @@ val IrFunctionReference.typeSubstitutionMap: Map<IrTypeParameterSymbol, IrType>
 
 val IrFunctionAccessExpression.typeSubstitutionMap: Map<IrTypeParameterSymbol, IrType>
     get() = getTypeSubstitutionMap(symbol.owner)
+
+// Perhaps move to some even more general utilities?
+fun String.toLowerCase() = toLowerCase(Locale.ROOT)
+fun String.toUpperCase() = toUpperCase(Locale.ROOT)