Fix Toy Ch3 testing with CMake

Mainly a missing dependency caused the tests to pass if one already built
    the repo, but not from a clean (or incremental) build.

--

PiperOrigin-RevId: 241852313

mlir/test/CMakeLists.txt

@@ -30,6 +30,7 @@ if(LLVM_BUILD_EXAMPLES)
   list(APPEND MLIR_TEST_DEPENDS
     toyc-ch1
     toyc-ch2
+    toyc-ch3
     )
 endif()
 

mlir/test/Examples/Toy/Ch3/scalar.toy

@@ -1,3 +1,5 @@
+# RUN: toyc-ch3 %s -emit=mlir 2>&1 | FileCheck %s
+
 def main() {
   var a<2, 2> = 5.5;
   print(a);

mlir/test/lit.cfg.py

@@ -59,6 +59,7 @@ tools = [
 tools.extend([
     ToolSubst('toy-ch1', unresolved='ignore'),
     ToolSubst('toy-ch2', unresolved='ignore'),
+    ToolSubst('toy-ch3', unresolved='ignore'),
 ])
 
 llvm_config.add_tool_substitutions(tools, tool_dirs)