JVM IR: substitute generic type for inline class replacement function calls

The main change here is in `JvmInlineClassLowering.visitFunctionAccess`,
where we now store the substituted return type of the function as the
type of the call expression. Without it, the call could have a
meaningless type, e.g. some `T` which is inaccessible at that place, and
that could backfire in subsequent lowerings in codegen. For example, in
the `stringPlus.kt` test, it would prevent the code in
`FlattenStringConcatenationLowering.isStringPlusCall` from recognizing
and replacing the `String.plus` call, leading to a codegen exception.

Other changes are mostly cosmetics to make the code similar to
`visitFunctionReference`, and preventive optimizations for the case when
the substitution map is empty.

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -15517,6 +15517,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");