when: emit lookupswitch/tableswitch if possible

A lookupswitch or tableswitch can be used if all conditions are equality
checks to constants. To be more specific, it can be done if:
  1. All conditions are CALL 'EQEQ(Any?, Any?)': Boolean
  2. All types of variables involved in comparison are in the same group
     of Char/Byte/Short/Int, String or enum.
  3. All arg0 refer to the same value.
  4. All arg1 are IrConst<*>.

Change-Id: Ifd7cb618395f6c5cc64601018b446f0bb7f5891c

compiler/testData/codegen/bytecodeText/when/tableSwitch.kt

@@ -0,0 +1,11 @@
+fun foo(x: Int): String {
+    return when (x) {
+        101 -> "1"
+        102 -> "2"
+        103 -> "3"
+        else -> "else"
+    }
+}
+
+// 0 LOOKUPSWITCH
+// 1 TABLESWITCH