Add wasm-merge test

test/lit/merge/sourcemap.wat

@@ -0,0 +1,27 @@
+;; NOTE: Assertions have been generated by update_lit_checks.py --all-items and should not be edited.
+
+;; RUN: wasm-merge %s first %s.second second -S -o - | filecheck %s
+
+;; Test that we fuse imports to exports across modules.
+
+(module
+  (func (export "f")
+     ;;@ a:1:1
+     (nop)
+  )
+)
+;; CHECK:      (type $0 (func))
+
+;; CHECK:      (export "f" (func $0))
+
+;; CHECK:      (export "g" (func $0_1))
+
+;; CHECK:      (func $0
+;; CHECK-NEXT:  ;;@ a:1:1
+;; CHECK-NEXT:  (nop)
+;; CHECK-NEXT: )
+
+;; CHECK:      (func $0_1
+;; CHECK-NEXT:  ;;@ b:2:2
+;; CHECK-NEXT:  (nop)
+;; CHECK-NEXT: )

test/lit/merge/sourcemap.wat.second

@@ -0,0 +1,6 @@
+(module
+  (func (export "g")
+     ;;@ b:2:2
+     (nop)
+  )
+)