Fix CMake Android cross-compilation on Windows. (#3459)

Fixes https://github.com/google/iree/issues/3457

* CMake targets shouldn't have executable suffixes (e.g. `.exe`) in them and `flatcc_cli.exe` was getting copied to `flatcc_cli` (dropping the extension where it matters).

* `iree_get_build_command` should take a target name, not an executable name (alias).

  The generated commands are of the format:
  ```
  C:/Program Files/CMake/bin/cmake.exe;--build;D:/dev/projects/iree-build-android/host;--target;iree-tblgen;-- config;$<CONFIG>
  ```
  Where `--target iree-tblgen` can't find the target on my system, but `--target iree_tools_iree-tblgen` can.

  I tried using `get_target_property(... ALIASED_TARGET)` but I get this error:
  `get_target_property() called with non-existent target "iree-translate"`
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 701ba0d..472cea2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -394,8 +394,8 @@
 if(CMAKE_CROSSCOMPILING)
   # We need flatc to generate some source code. When cross-compiling, we need
   # to make sure the flatc binary is configured under host environment.
-  iree_declare_host_excutable(flatc BUILDONLY)
-  iree_declare_host_excutable(flatcc_cli BUILDONLY)
+  iree_declare_host_excutable(flatc "flatc" BUILDONLY)
+  iree_declare_host_excutable(flatcc_cli "flatcc_cli" BUILDONLY)
 
   # Set the FLATBUFFERS_FLATC_EXECUTABLE. It controls where to find the flatc
   # binary in BuildFlatBuffers().
@@ -414,7 +414,7 @@
     COMMAND
       "${CMAKE_COMMAND}" -E copy_if_different
         "${PROJECT_SOURCE_DIR}/third_party/flatcc/bin/flatcc${IREE_HOST_EXECUTABLE_SUFFIX}"
-        "${IREE_HOST_BINARY_ROOT}/bin/flatcc_cli"
+        "${IREE_HOST_BINARY_ROOT}/bin/flatcc_cli${IREE_HOST_EXECUTABLE_SUFFIX}"
     DEPENDS iree_host_build_flatcc_cli
     COMMENT "Installing host flatcc..."
   )