infra: use m5.xlarge instances for "ap-northeast-1" region integ tests. (#1388)

Author: nadiaya

tests/conftest.py

@@ -31,7 +31,14 @@
 
 DEFAULT_REGION = "us-west-2"
 
-NO_M4_REGIONS = ["eu-west-3", "eu-north-1", "ap-east-1", "sa-east-1", "me-south-1"]
+NO_M4_REGIONS = [
+    "eu-west-3",
+    "eu-north-1",
+    "ap-east-1",
+    "ap-northeast-1",  # it has m4.xl, but not enough in all AZs
+    "sa-east-1",
+    "me-south-1",
+]
 
 NO_T2_REGIONS = ["eu-north-1", "ap-east-1", "me-south-1"]