Add tests for issues fixed in JVM IR

Note that KT-30696 is fixed only in the single-module case, and KT-42012
is not fixed fully (see KT-44855).

 #KT-30041
 #KT-30629
 #KT-30696
 #KT-30933
 #KT-32351
 #KT-32749
 #KT-38849
 #KT-42012
 #KT-42990
 #KT-44234
 #KT-44529
 #KT-44631
 #KT-44647

compiler/testData/codegen/box/operatorConventions/kt44647.kt

@@ -0,0 +1,11 @@
+// IGNORE_BACKEND: JVM
+// IGNORE_LIGHT_ANALYSIS
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: STDLIB_STRING_BUILDER
+// WITH_RUNTIME
+
+fun box(): String {
+    val sb = StringBuilder("NK")
+    sb[0]++
+    return sb.toString()
+}