RFR: 8262093: java/util/concurrent/tck/JSR166TestCase.java failed "assert(false) failed: unexpected node"

[Vladimir Kozlov]

LoadStore node misses Value() method which checks for Top inputs. As result dead data IR subgraph was not removed. Control subgraph is not eliminated because of complicated loop. 

The fix is to add missing Value() method.
Small refactoring in StoreCMNode::Value() because StoreNode::Value() already has checks for TOP edges.
Added check to SCMemProjNode::Value() which led to changes in GraphKit::compress_string() where call to transform() was missing.
Dumping additional info for asserts and code style fixes in macro.cpp.

Tested tier1-4 and xcomp.

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Commit messages:
 - Merge branch 'master' into JDK-8262093
 - 8262093: java/util/concurrent/tck/JSR166TestCase.java failed "assert(false) failed: unexpected node"

Changes: https://git.openjdk.java.net/jdk/pull/3226/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3226&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8262093
  Stats: 60 lines in 4 files changed: 43 ins; 8 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3226.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3226/head:pull/3226

PR: https://git.openjdk.java.net/jdk/pull/3226