Add test case to verify CMake does not re-run on first build

Extend the RunCMake.Configure with a case to verify that the CMake
configuration process does not immediately re-run the first time that
the generated build system is invoked.

Tests/RunCMake/Configure/RerunCMake-build1-check.cmake

@@ -0,0 +1,4 @@
+file(READ ${stamp} content)
+if(NOT content STREQUAL 1)
+  set(RunCMake_TEST_FAILED "Expected stamp '1' but got: '${content}'")
+endif()

Tests/RunCMake/Configure/RerunCMake.cmake

@@ -0,0 +1,4 @@
+set(input  ${CMAKE_CURRENT_BINARY_DIR}/CustomCMakeInput.txt)
+set(stamp  ${CMAKE_CURRENT_BINARY_DIR}/CustomCMakeStamp.txt)
+file(READ ${input} content)
+file(WRITE ${stamp} "${content}")

Tests/RunCMake/Configure/RunCMakeTest.cmake

@@ -2,3 +2,18 @@ include(RunCMake)
 
 run_cmake(ErrorLogs)
 run_cmake(FailCopyFileABI)
+
+# Use a single build tree for a few tests without cleaning.
+set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/RerunCMake-build)
+set(RunCMake_TEST_NO_CLEAN 1)
+file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+set(input  "${RunCMake_TEST_BINARY_DIR}/CustomCMakeInput.txt")
+set(stamp  "${RunCMake_TEST_BINARY_DIR}/CustomCMakeStamp.txt")
+file(WRITE "${input}" "1")
+run_cmake(RerunCMake)
+execute_process(COMMAND ${CMAKE_COMMAND} -E sleep 1) # handle 1s resolution
+file(WRITE "${input}" "2")
+run_cmake_command(RerunCMake-build1 ${CMAKE_COMMAND} --build .)
+unset(RunCMake_TEST_BINARY_DIR)
+unset(RunCMake_TEST_NO_CLEAN)