bake: more test cases

[crazy-max]

relates to:

• [v0.19.0] bake: Unsuitable value: EOF #2822
• [v0.19.0] bake: cache-to/cache-from attributes output credentials with --print #2823

fixes #2825

They are expected to fail currently:

https://github.com/docker/buildx/actions/runs/12066463568/job/33647355827?pr=2826#step:6:1322

=== FAIL: bake TestEmptyAttribute (0.00s)
    bake_test.go:2037: 
        	Error Trace:	/home/runner/work/buildx/buildx/bake/bake_test.go:2037
        	Error:      	Received unexpected error:
        	            	docker-bake.hcl:3,12-13: Unsuitable value type; Unsuitable value: EOF
        	Test:       	TestEmptyAttribute

https://github.com/docker/buildx/actions/runs/12066463568/job/33647354770?pr=2826#step:7:508

=== FAIL: tests TestIntegration/TestBakePrint/worker=docker-container (1.22s)
    bake.go:123: 
        	Error Trace:	/src/tests/bake.go:123
        	            				/src/vendor/github.com/moby/buildkit/util/testutil/integration/run.go:97
        	            				/src/vendor/github.com/moby/buildkit/util/testutil/integration/run.go:211
        	Error:      	Not equal: 
        	            	expected: []*buildflags.CacheOptionsEntry{(*buildflags.CacheOptionsEntry)(0xc000957e90), (*buildflags.CacheOptionsEntry)(0xc000957ea8), (*buildflags.CacheOptionsEntry)(0xc000957ec0)}
        	            	actual  : []*buildflags.CacheOptionsEntry{(*buildflags.CacheOptionsEntry)(0xc000957c98), (*buildflags.CacheOptionsEntry)(0xc000957cc8), (*buildflags.CacheOptionsEntry)(0xc000957cf8)}
        	            	
        	            	Diff:
        	            	--- Expected
        	            	+++ Actual
        	            	@@ -3,4 +3,5 @@
        	            	   Type: (string) (len=3) "gha",
        	            	-  Attrs: (map[string]string) (len=1) {
        	            	-   (string) (len=5) "scope": (string) (len=5) "build"
        	            	+  Attrs: (map[string]string) (len=2) {
        	            	+   (string) (len=5) "scope": (string) (len=5) "build",
        	            	+   (string) (len=5) "token": (string) (len=3) "baz"
        	            	   }
        	            	@@ -9,5 +10,7 @@
        	            	   Type: (string) (len=2) "s3",
        	            	-  Attrs: (map[string]string) (len=2) {
        	            	+  Attrs: (map[string]string) (len=4) {
        	            	+   (string) (len=13) "access_key_id": (string) (len=3) "foo",
        	            	    (string) (len=6) "bucket": (string) (len=8) "mybucket",
        	            	-   (string) (len=6) "region": (string) (len=9) "eu-west-1"
        	            	+   (string) (len=6) "region": (string) (len=9) "eu-west-1",
        	            	+   (string) (len=17) "secret_access_key": (string) (len=3) "bar"
        	            	   }
        	            	@@ -15,4 +18,6 @@
        	            	  (*buildflags.CacheOptionsEntry)({
        	            	-  Type: (string) (len=15) "user/repo:cache",
        	            	-  Attrs: (map[string]string) <nil>
        	            	+  Type: (string) (len=8) "registry",
        	            	+  Attrs: (map[string]string) (len=1) {
        	            	+   (string) (len=3) "ref": (string) (len=15) "user/repo:cache"
        	            	+  }
        	            	  })
        	Test:       	TestIntegration/TestBakePrint/worker=docker-container