Migrate deprecations in core, compiler, idea, tests

Replacing deprecated Char.toInt() with Char.code and
Number.toChar() with Number.toInt().toChar(), where Number is not Int.

KT-23451

js/js.frontend/src/org/jetbrains/kotlin/js/resolve/diagnostics/JsCallChecker.kt

@@ -167,7 +167,7 @@ private fun String.offsetOf(position: CodePosition): Int {
         i++
         offsetInLine++
 
-        if (isEndOfLine(c.toInt())) {
+        if (isEndOfLine(c.code)) {
             offsetInLine = 0
             lineCount++
             assert(lineCount <= position.line)

js/js.frontend/src/org/jetbrains/kotlin/js/resolve/diagnostics/jsRenderers.kt

@@ -80,7 +80,7 @@ fun String.underlineAsText(from: Int, to: Int): String {
         marks.append(mark)
         lineWasMarked = lineWasMarked || mark != ' '
 
-        if (isEndOfLine(c.toInt())) {
+        if (isEndOfLine(c.code)) {
             if (lineWasMarked) {
                 lines.appendLine(marks.toString().trimEnd())
                 lineWasMarked = false
@@ -121,7 +121,7 @@ fun String.underlineAsHtml(from: Int, to: Int): String {
 
         lines.append(mark)
 
-        if (isEndOfLine(c.toInt()) && openMarker) {
+        if (isEndOfLine(c.code) && openMarker) {
             lines.append(underlineEnd + c + underlineStart)
         } else {
             lines.append(c)

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/JSON.kt

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
+@file:Suppress("DEPRECATION") // TODO: needs an intensive rework for new Char API
 package org.jetbrains.kotlin.js.parser.sourcemaps
 
 import java.io.*

js/js.parser/src/org/jetbrains/kotlin/js/parser/sourcemaps/SourceMapParser.kt

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+@file:Suppress("DEPRECATION") // TODO: needs an intensive rework for new Char API
 package org.jetbrains.kotlin.js.parser.sourcemaps
 
 import java.io.File

js/js.translator/src/org/jetbrains/kotlin/js/translate/expression/WhenTranslator.kt

@@ -197,7 +197,7 @@ private constructor(private val whenExpression: KtWhenExpression, context: Trans
                         is Int -> JsIntLiteral(it)
                         is Short -> JsIntLiteral(it.toInt())
                         is Byte -> JsIntLiteral(it.toInt())
-                        is Char -> JsIntLiteral(it.toInt())
+                        is Char -> JsIntLiteral(it.code)
                         else -> null
                     }
                 }