Remove obsolete properties. (#48753)

These properties were used within recipes to generate the gn and ninja commands for the different platforms. With V2 gn commands and its properties are set explicitly and the properties are not required anymore.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: godofredoc

.ci.yaml

@@ -13,17 +13,6 @@ enabled_branches:
 platform_properties:
   linux:
     properties:
-      build_host: "false"
-      build_fuchsia: "false"
-      build_android_debug: "false"
-      build_android_aot: "false"
-      build_android_vulkan: "false"
-      build_ios: "false"
-      build_android_jit_release: "false"
-      gcs_goldens_bucket: ""
-      ios_debug: "false"
-      ios_profile: "false"
-      ios_release: "false"
       # CIPD flutter/java/openjdk/$platform
       dependencies: >-
         [
@@ -35,17 +24,6 @@ platform_properties:
       cores: "8"
   mac:
     properties:
-      build_host: "false"
-      build_fuchsia: "false"
-      build_android_debug: "false"
-      build_android_aot: "false"
-      build_android_vulkan: "false"
-      build_ios: "false"
-      build_android_jit_release: "false"
-      gcs_goldens_bucket: ""
-      ios_debug: "false"
-      ios_profile: "false"
-      ios_release: "false"
       # CIPD flutter/java/openjdk/$platform
       dependencies: >-
         [
@@ -65,17 +43,6 @@ platform_properties:
       mac_model: "Macmini8,1|Macmini9,1"
   windows:
     properties:
-      build_host: "false"
-      build_fuchsia: "false"
-      build_android_debug: "false"
-      build_android_aot: "false"
-      build_android_vulkan: "false"
-      build_ios: "false"
-      build_android_jit_release: "false"
-      gcs_goldens_bucket: ""
-      ios_debug: "false"
-      ios_profile: "false"
-      ios_release: "false"
       # CIPD flutter/java/openjdk/$platform
       dependencies: >-
         [