[Do not merge] Specify `Accept` header for `toolcache.downloadTool` #5692

Job	Run time
Go: tracing with custom build steps (ubuntu-latest, stable-v2.17.6)	1m 9s
Go: tracing with custom build steps (macos-latest, stable-v2.18.4)	2m 31s
Go: tracing with custom build steps (macos-latest, stable-v2.17.6)	2m 16s
Go: tracing with custom build steps (ubuntu-latest, stable-v2.22.4)	1m 10s
Go: tracing with custom build steps (ubuntu-latest, stable-v2.19.4)	1m 21s
Go: tracing with custom build steps (macos-latest, stable-v2.19.4)	2m 13s
Go: tracing with custom build steps (ubuntu-latest, stable-v2.18.4)	1m 17s
Go: tracing with custom build steps (ubuntu-latest, linked)	59s
Go: tracing with custom build steps (macos-latest, stable-v2.20.7)	2m 29s
Go: tracing with custom build steps (ubuntu-latest, nightly-latest)	1m 3s
Go: tracing with custom build steps (ubuntu-latest, stable-v2.20.7)	1m 9s
Go: tracing with custom build steps (macos-latest, nightly-latest)	2m 42s
Go: tracing with custom build steps (ubuntu-latest, default)	55s
Go: tracing with custom build steps (macos-latest, default)	2m 41s
Go: tracing with custom build steps (ubuntu-latest, stable-v2.21.4)	1m 29s
Go: tracing with custom build steps (macos-latest, stable-v2.21.4)	2m 38s
Go: tracing with custom build steps (macos-latest, stable-v2.22.4)	2m 4s
Go: tracing with custom build steps (macos-latest, linked)	2m 23s
	32m 29s

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