Support personal openj9 sha without branch (#3184)

Currently, we take both OPENJ9_BRANCH and OPENJ9_SHA. However, in testenv.properties, we only output one value
 - OPENJ9_SHA (adoptium/TKG#255). We will not have branch information. The logic in `get.sh` was highly optimized
 to have minimal checkout for openj9 repo (i.e., we do not fetch other branches). This causes a problem as it is
 not able to git clone with sha only (if the sha is from other branch).

This PR adds the support to git clone personal openj9 sha without branch info, so we can consume the OPENJ9_SHA
without OPENJ9_BRNACH info.

Related: adoptium/TKG#255
Related: #2889

Signed-off-by: lanxia lan_xia@ca.ibm.com

get.sh

@@ -484,7 +484,13 @@ getFunctionalTestMaterial()
 			echo "git fetch -q --tags $OPENJ9_REPO +refs/pull/*:refs/remotes/origin/pr/*"
 			git fetch -q --tags $OPENJ9_REPO +refs/pull/*:refs/remotes/origin/pr/*
 			echo "git checkout -q $OPENJ9_SHA"
-			git checkout -q $OPENJ9_SHA
+			if ! git checkout $OPENJ9_SHA; then
+				echo "SHA not yet found. Continue fetching all the branches on origin..."
+				echo "git fetch -q --tags $OPENJ9_REPO +refs/heads/*:refs/remotes/origin/*"
+				git fetch -q --tags $OPENJ9_REPO +refs/heads/*:refs/remotes/origin/*
+				echo "git checkout -q $OPENJ9_SHA"
+				git checkout $OPENJ9_SHA
+			fi
 		fi
 		cd $TESTDIR
 	fi