ffi 2.2 xfail: instance method body item in #jni_class

`Foo :: #jni_class("path") { getId :: (self: *Self) -> s32; }`
should parse, today's 2.1 parser rejects any non-empty body. The
make-green follow-up extends parseJniClassDecl to loop over body
items collecting method declarations.

examples/ffi-jni-class-02-method.sx

@@ -0,0 +1,20 @@
+// Phase 2 step 2.2 (PLAN-FFI.md): xfail then green for the instance
+// method body item inside a `#jni_class` declaration.
+//
+// `name :: (self: *Self, args...) -> Ret;` is the shape — semicolon
+// terminated (foreign declaration, no body). The 2.1 parser only
+// accepts an empty body; step 2.2 extends `parseJniClassDecl` to
+// loop over body items and collect method declarations.
+
+#import "modules/std.sx";
+
+// `Self` here refers to the enclosing `View` type — resolved at
+// 2.x sema, not at parse time.
+View :: #jni_class("android/view/View") {
+    getId :: (self: *Self) -> s32;
+}
+
+main :: () -> s32 {
+    print("parse-only ok\n");
+    0;
+}

tests/expected/ffi-jni-class-02-method.exit

@@ -0,0 +1 @@
+1

tests/expected/ffi-jni-class-02-method.txt

@@ -0,0 +1 @@
+/Users/agra/projects/sx/examples/ffi-jni-class-02-method.sx:14:5: error: non-empty `#jni_class` body not yet supported (Phase 2.1 accepts only the empty/opaque form)