twister: add support for platform_type filter

Instead of relying on runtime filter to limit scope to emulation
platforms, use the type attribute for each platform and do the filtering
very early on. This will speed things up for tests where we only run on
emulation platforms.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

scripts/schemas/twister/testsuite-schema.yaml

@@ -104,6 +104,11 @@ mapping:
       "platform_allow":
         type: str
         required: false
+      "platform_type":
+        type: seq
+        required: false
+        sequence:
+          - type: str
       "tags":
         type: str
         required: false
@@ -247,6 +252,11 @@ mapping:
           "platform_allow":
             type: str
             required: false
+          "platform_type":
+            type: seq
+            required: false
+            sequence:
+              - type: str
           "tags":
             type: str
             required: false