RFR: 8286800: Assert in PhaseIdealLoop::dump_real_LCA is too strong

[Dhamoder Nalla]

https://bugs.openjdk.org/browse/JDK-8286800

assert(real_LCA != NULL) in dump_real_LCA is not appropriate in bad graph scenario when both wrong_lca & early nodes are start nodes

jvm!PhaseIdealLoop::dump_real_LCA():
// Walk the idom chain up from early and wrong_lca and stop when they intersect.
while (!n1->is_Start() && !n2->is_Start()) {
...
}
assert(real_LCA != NULL, "must always find an LCA");

Fix: replace assert with a console message

-------------

Commit messages:
 - remove spaces
 - Assert in PhaseIdealLoop::dump_real_LCA is too strong

Changes: https://git.openjdk.org/jdk/pull/10472/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10472&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8286800
  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/10472.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10472/head:pull/10472

PR: https://git.openjdk.org/jdk/pull/10472