[Wasm] Add compiler flag to disable exception handling proposal

Fail with unreachable instead of throwing an exception

Merge-request: KT-MR-11481
Merged-by: Svyatoslav Kuzmich <svyatoslav.kuzmich@jetbrains.com>

compiler/testData/cli/js/jsExtraHelp.out

@@ -60,6 +60,8 @@ where advanced options include:
   -Xwasm-generate-wat        Generate wat file
   -Xwasm-kclass-fqn          Enable support for FQ names in KClass
   -Xwasm-target              Set up Wasm target (wasm-js or wasm-wasi)
+  -Xwasm-use-traps-instead-of-exceptions
+                             Trap instead of throwing exceptions
   -Xallow-any-scripts-in-source-roots
                              Allow to compile any scripts along with regular Kotlin sources
   -Xallow-kotlin-package     Allow compiling code in package 'kotlin' and allow not requiring kotlin.stdlib in module-info

compiler/testData/codegen/boxWasmJsInterop/noExceptions.kt

@@ -0,0 +1,46 @@
+// TARGET_BACKEND: WASM
+// DISABLE_WASM_EXCEPTION_HANDLING
+// MODULE: main
+// FILE: foo.kt
+
+@JsExport
+fun sumNumbers(x: Int): Int =
+    (0..x).toList().sum()
+
+@JsExport
+fun add(x: Int, y: Int): Int =
+    x + y
+
+@JsExport
+fun throws() {
+    try {
+        error("Test Error")
+    } catch (e: Throwable) {
+        // This code normally catches the error,
+        // but with exception handling disabled it should fail with trap
+    }
+}
+
+
+// FILE: entry.mjs
+
+import wasmExports from "./index.mjs";
+
+if (wasmExports.add(10, 20) !== 30) {
+    throw "Fail add";
+}
+
+if (wasmExports.sumNumbers(10) !== 55) {
+    throw "Fail sumNumbers";
+}
+
+var thrown = false;
+try {
+    wasmExports.throws();
+} catch(e) {
+    thrown = true;
+}
+
+if (!thrown) {
+    throw "Fail exception was not thrown";
+}