[TEST] Changed the possessive matching syntax in cat.recovery

regex to use an independent subexpression. Possessive
modifiers not supported on older Perl

rest-api-spec/test/cat.recovery/10_basic.yaml

@@ -24,7 +24,8 @@
   - match:
       $body: |
               /^
-              ( index1      \s+
+              (?>
+                index1      \s+
                 \d          \s+                                 # shard
                 \d+         \s+                                 # time
                 (gateway|replica|snapshot|relocating)     \s+   # type
@@ -38,5 +39,5 @@
                 \d+         \s+                                 # bytes
                 \d+\.\d+%    \s+                                # bytes_percent
                 \n
-              )++
+              )+
               $/