8200375: Change to GCC 7.3.0 for building Linux at Oracle

Reviewed-by: ihse, tbell

make/conf/jib-profiles.js

@@ -816,7 +816,7 @@ var getJibProfilesProfiles = function (input, common, data) {
 var getJibProfilesDependencies = function (input, common) {
 
     var devkit_platform_revisions = {
-        linux_x64: "gcc4.9.2-OEL6.4+1.3",
+        linux_x64: "gcc7.3.0-OEL6.4+1.0",
         macosx_x64: "Xcode6.3-MacOSX10.9+1.0",
         solaris_x64: "SS12u4-Solaris11u1+1.0",
         solaris_sparcv9: "SS12u4-Solaris11u1+1.1",