fix:delete trailing whitespace

Author: korzhao

src/cmd/go/internal/test/test.go

@@ -119,14 +119,14 @@ elapsed time in the summary line.
 The rule for a match in the cache is that the run involves the same
 test binary and the flags on the command line come entirely from a
 restricted set of 'cacheable' test flags, defined as -benchtime, -cpu,
--list, -parallel, -run, -short, -timeout, -failfast, and -v. 
-If a run of go test has any test or non-test flags outside this set, 
-the result is not cached. To disable test caching, use any test flag 
+-list, -parallel, -run, -short, -timeout, -failfast, and -v.
+If a run of go test has any test or non-test flags outside this set,
+the result is not cached. To disable test caching, use any test flag
 or argument other than the cacheable flags. The idiomatic way to disable
 test caching explicitly is to use -count=1. Tests that open files within
-the package's source root (usually $GOPATH) or that consult environment 
+the package's source root (usually $GOPATH) or that consult environment
 variables only match future runs in which the files and environment
-variables are unchanged. A cached test result is treated as executing 
+variables are unchanged. A cached test result is treated as executing
 in no time at all,so a successful package test result will be cached and
 reused regardless of -timeout setting.