Test fix - reenable BWC tests and lower version checks now that PR 28440 for allowPartialSearchResults flag backported to 6.x (#28482)

Support for allowPartialSearchResults is now in 6.3 so changing master BWC checks accordingly

build.gradle

@@ -145,7 +145,7 @@ task verifyVersions {
  * after the backport of the backcompat code is complete.
  */
 allprojects {
-  ext.bwc_tests_enabled = false
+  ext.bwc_tests_enabled = true
 }
 
 task verifyBwcTestsEnabled {

server/src/main/java/org/elasticsearch/action/search/SearchRequest.java

@@ -138,7 +138,7 @@ public final class SearchRequest extends ActionRequest implements IndicesRequest
             maxConcurrentShardRequests = in.readVInt();
             preFilterShardSize = in.readVInt();
         }
-        if (in.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (in.getVersion().onOrAfter(Version.V_6_3_0)) {
             allowPartialSearchResults = in.readOptionalBoolean();
         }           
     }
@@ -163,7 +163,7 @@ public final class SearchRequest extends ActionRequest implements IndicesRequest
             out.writeVInt(maxConcurrentShardRequests);
             out.writeVInt(preFilterShardSize);
         }
-        if (out.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (out.getVersion().onOrAfter(Version.V_6_3_0)) {
             out.writeOptionalBoolean(allowPartialSearchResults);
         }         
     }

server/src/main/java/org/elasticsearch/search/internal/ShardSearchLocalRequest.java

@@ -222,7 +222,7 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         if (in.getVersion().onOrAfter(Version.V_5_6_0)) {
             clusterAlias = in.readOptionalString();
         }
-        if (in.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (in.getVersion().onOrAfter(Version.V_6_3_0)) {
             allowPartialSearchResults = in.readOptionalBoolean();
         }
     }
@@ -247,7 +247,7 @@ public class ShardSearchLocalRequest implements ShardSearchRequest {
         if (out.getVersion().onOrAfter(Version.V_5_6_0)) {
             out.writeOptionalString(clusterAlias);
         }
-        if (out.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+        if (out.getVersion().onOrAfter(Version.V_6_3_0)) {
             out.writeOptionalBoolean(allowPartialSearchResults);
         }