RFR: 8326438: C2: assert(ld->in(1)->Opcode() == Op_LoadN) failed: Assumption invalid: input to DecodeN is not LoadN

[Daniel Lundén]

The [`assert`](https://github.com/openjdk/jdk/blob/6f2676dc5f09d350c359f906b07f6f6d0d17f030/src/hotspot/share/opto/graphKit.cpp#L1567) added in [JDK-8310524](https://bugs.openjdk.org/browse/JDK-8310524) is too strong and may sometimes not hold due to the [GVN transformation in `LoadNode::make`](https://github.com/openjdk/jdk/blob/8cb9b479c529c058aee50f83920db650b0c18045/src/hotspot/share/opto/memnode.cpp#L973).

### Changeset
Remove the `assert`.

### Testing
N/A

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

Commit messages:
 - Remove assert

Changes: https://git.openjdk.org/jdk/pull/18434/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18434&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8326438
  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/18434.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18434/head:pull/18434

PR: https://git.openjdk.org/jdk/pull/18434