Clean up some WebGL expectations

tests/wpt/webgl/meta/conformance/glsl/misc/fragcolor-fragdata-invariant.html.ini

@@ -1,4 +1,5 @@
 [fragcolor-fragdata-invariant.html]
+  bug: https://github.com/servo/servo/issues/20601
   [WebGL test #0: [unexpected fragment shader compile status\] (expected: true) Declaring both gl_FragColor and gl_FragData invariant should succeed.]
     expected: FAIL
 

tests/wpt/webgl/meta/conformance/glsl/misc/shader-with-define-line-continuation.frag.html.ini

@@ -1,6 +1,5 @@
 [shader-with-define-line-continuation.frag.html]
   bug: https://github.com/servo/servo/issues/20601
-  type: testharness
   [WebGL test #0: [unexpected link status\] fragment shader that uses line continuation macro should fail]
     expected: FAIL
 

tests/wpt/webgl/meta/conformance/glsl/misc/shader-with-global-variable-precision-mismatch.html.ini

@@ -1,6 +1,5 @@
 [shader-with-global-variable-precision-mismatch.html]
   bug: https://github.com/servo/servo/issues/20601
-  type: testharness
   [WebGL test #0: [unexpected link status\] mismatching precision for uniforms causes link error (as expected)]
     expected: FAIL
 

tests/wpt/webgl/meta/conformance/glsl/misc/shaders-with-uniform-structs.html.ini

@@ -1,6 +1,5 @@
 [shaders-with-uniform-structs.html]
   bug: https://github.com/servo/servo/issues/20601
-  type: testharness
   [WebGL test #5: [unexpected link status\] Structures must have the same type definitions (including precision) to be considered the same type.]
     expected: FAIL
 

tests/wpt/webgl/meta/conformance/glsl/misc/shaders-with-varyings.html.ini

@@ -1,6 +1,5 @@
 [shaders-with-varyings.html]
   bug: https://github.com/servo/servo/issues/20601
-  type: testharness
   [WebGL test #3: [unexpected link status\] vertex shader with unused varying and fragment shader with used varying must succeed]
     expected: FAIL