Capitalize/decapitalize only ASCII characters across project

Use {de,}capitalizeAsciiOnly and to{Lower,Upper}CaseAsciiOnly where
possible, and stdlib's functions with Locale.US everywhere else.

Otherwise, if the default system locale is Turkish, the capital latin
letter "I" is transformed in toLowerCase to "ı" (see
https://github.com/JetBrains/kotlin/blob/66bc142f92085047a1ca64f9a291f0496e33dd98/libraries/stdlib/jvm/test/text/StringJVMTest.kt#L119),
which for example breaks the codegen for `intArrayOf` in
KT-25400/KT-43405.

Similarly, lower case latin letter "i" is transformed to "İ".

 #KT-13631 Fixed
 #KT-25400 Fixed
 #KT-43405 Fixed

js/js.frontend/src/org/jetbrains/kotlin/js/config/ErrorTolerancePolicy.kt

@@ -5,6 +5,8 @@
 
 package org.jetbrains.kotlin.js.config
 
+import java.util.*
+
 enum class ErrorTolerancePolicy(val allowSyntaxErrors: Boolean, val allowSemanticErrors: Boolean) {
     NONE(false, false),
     SEMANTIC(false, true),
@@ -16,7 +18,7 @@ enum class ErrorTolerancePolicy(val allowSyntaxErrors: Boolean, val allowSemanti
         val DEFAULT = NONE
 
         fun resolvePolicy(key: String): ErrorTolerancePolicy {
-            return when (key.toUpperCase()) {
+            return when (key.toUpperCase(Locale.US)) {
                 "NONE" -> NONE
                 "SEMANTIC" -> SEMANTIC
                 "SYNTAX", "ALL" -> ALL
@@ -24,4 +26,4 @@ enum class ErrorTolerancePolicy(val allowSyntaxErrors: Boolean, val allowSemanti
             }
         }
     }
-}
+}