Use string.format to fix floating point error in test output

changelog.md

@@ -3,6 +3,7 @@
 ## Unreleased
 <!-- Add all new changes here. They will be moved under a version at release -->
 * `NEW` Added support for Japanese locale
+* `FIX` Eliminate floating point error in test benchmark output
 * `FIX` Remove luamake install from make scripts
 
 ## 3.10.6

test/full/projects.lua

@@ -49,7 +49,7 @@ local function doProjects(pathname)
     for uri in files.eachFile() do
         local fileClock = os.clock()
         diag.doDiagnostic(uri, true)
-        print('诊断文件耗时：', os.clock() - fileClock, uri)
+        print('诊断文件耗时：', string.format("%.6f", os.clock() - fileClock), uri)
     end
 
     local passed = os.clock() - clock

test/full/self.lua

@@ -48,7 +48,7 @@ for uri in files.eachFile() do
     end)
     local fileClock = os.clock()
     diag.doDiagnostic(uri, true)
-    print('诊断文件耗时：', os.clock() - fileClock, uri)
+    print('诊断文件耗时：', string.format("%.6f", os.clock() - fileClock), uri)
     ::CONTINUE::
 end