[Wasm] Add @WasmImport diagnostics (KT-56943)

WasmImport annotated functions:
* Restricted to top-level external functions
* Only supports primitive numbers, booleans and Unit
  (as return type only) in its signature
* Can't have default parameter values
* Can't have vararg parameters

compiler/testData/diagnostics/wasmTests/wasmInterop/wasmImport.kt

@@ -0,0 +1,49 @@
+import kotlin.wasm.WasmImport
+
+@WasmImport("a", "b")
+external fun foo0(): Unit
+
+<!WASM_IMPORT_ON_NON_EXTERNAL_DECLARATION!>@WasmImport("a", "b")<!>
+fun foo1() {
+}
+
+external class C {
+    <!NESTED_WASM_IMPORT!>@WasmImport("a", "b")<!>
+    fun memberFunction()
+}
+
+fun foo2() {
+    <!NESTED_WASM_IMPORT, WASM_IMPORT_ON_NON_EXTERNAL_DECLARATION!>@WasmImport("a", "b")<!>
+    fun localFun() {
+    }
+}
+
+val p1 = (<!NESTED_WASM_IMPORT, WASM_IMPORT_ON_NON_EXTERNAL_DECLARATION!>@WasmImport("a", "b")<!> fun () {})
+
+@WasmImport("a", "b")
+external fun foo3(
+    <!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE!>p0: Unit<!>,
+    <!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE!>p1: String<!>,
+    <!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE!>p2: Any<!>,
+    <!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE!>p3: Int?<!>,
+    <!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE!>p4: Boolean?<!>
+): Unit
+
+
+<!WASM_IMPORT_UNSUPPORTED_RETURN_TYPE!>@WasmImport("a", "b")
+external fun returnNullableUnit(): Unit?<!>
+
+<!WASM_IMPORT_UNSUPPORTED_RETURN_TYPE!>@WasmImport("a", "b")
+external fun returnNullableBoolean(): Boolean?<!>
+
+<!WASM_IMPORT_UNSUPPORTED_RETURN_TYPE!>@WasmImport("a", "b")
+external fun returnNullableAny(): Any?<!>
+
+<!WASM_IMPORT_UNSUPPORTED_RETURN_TYPE!>@WasmImport("a", "b")
+external fun <T> fooGeneric(<!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE!>x: T<!>): T<!>
+
+@WasmImport("a", "b")
+external fun fooDeafultAndVararg(
+    <!WASM_IMPORT_PARAMETER_DEFAULT_VALUE!>a: Int = definedExternally<!>,
+<!WASM_IMPORT_UNSUPPORTED_PARAMETER_TYPE, WASM_IMPORT_VARARG_PARAMETER!>vararg b: Int<!>
+): Unit