Tests/RunCMake/Emscripten: Add tests covering try_compile COPY_FILE

Compiler inspection relies on `try_compile`'s `COPY_FILE` option to copy
the `.wasm` file because the `.js` does not have the `INFO:size` string.

Issue: #27421

Tests/RunCMake/Emscripten/C-CheckTypeSize-stdout.txt

@@ -0,0 +1,2 @@
+-- SIZEOF_INT='[1-9][0-9]*'
+-- HAVE_SIZEOF_INT='TRUE'

Tests/RunCMake/Emscripten/C-CheckTypeSize.cmake

@@ -0,0 +1,6 @@
+enable_language(C)
+
+include(CheckTypeSize)
+check_type_size(int SIZEOF_INT)
+message(STATUS "SIZEOF_INT='${SIZEOF_INT}'")
+message(STATUS "HAVE_SIZEOF_INT='${HAVE_SIZEOF_INT}'")

Tests/RunCMake/Emscripten/C-enable-stdout.txt

@@ -0,0 +1,2 @@
+-- CMAKE_C_BYTE_ORDER='LITTLE_ENDIAN'
+-- CMAKE_C_SIZEOF_DATA_PTR='[1-9][0-9]*'

Tests/RunCMake/Emscripten/C-enable.cmake

@@ -0,0 +1,7 @@
+enable_language(C)
+foreach(var IN ITEMS
+    CMAKE_C_BYTE_ORDER
+    CMAKE_C_SIZEOF_DATA_PTR
+  )
+  message(STATUS "${var}='${${var}}'")
+endforeach()

Tests/RunCMake/Emscripten/RunCMakeTest.cmake

@@ -40,6 +40,12 @@ foreach(_emscripten_toolchain IN LISTS _emscripten_toolchains)
   set(cxx_comp ${BIN_DIR}/em++${EMCC_SUFFIX})
   set(comp_ar ${BIN_DIR}/emar${EMCC_SUFFIX})
 
+  # Compiler inspection.
+  run_cmake_with_options(C-enable
+    -DCMAKE_SYSTEM_NAME=Emscripten
+    -DCMAKE_C_COMPILER=${c_comp}
+  )
+
   # Create an executable from .c sources only.
   run_toolchain(C-exe
     -DCMAKE_SYSTEM_NAME=Emscripten
@@ -76,4 +82,9 @@ foreach(_emscripten_toolchain IN LISTS _emscripten_toolchains)
   )
   run_cmake_target(C-WHOLE_ARCHIVE link-exe main)
   run_cmake_target(C-WHOLE_ARCHIVE circular-exe main_circular)
+
+  run_cmake_with_options(C-CheckTypeSize
+    -DCMAKE_SYSTEM_NAME=Emscripten
+    -DCMAKE_C_COMPILER=${c_comp}
+  )
 endforeach()