RFR: 8253000: Remove redundant MAKE_SUBDIR argument

[Adam Farley]

As part of JDK-8244044, MAKE_SUBDIR is no longer used in DeclareRecipesForPhase inside MakeSupport.gmk.

Therefore, it seems sensible to modify the instances where this is passed to DeclareRecipesForPhase, and to remove
references to it from the associated MakeSupport.gmk comment.

Bug: https://bugs.openjdk.java.net/browse/JDK-8253000

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Commit messages:
 - 8253000: Remove redundant MAKE_SUBDIR argument

Changes: https://git.openjdk.java.net/jdk/pull/249/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=249&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8253000
  Stats: 7 lines in 2 files changed: 0 ins; 7 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/249.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/249/head:pull/249

PR: https://git.openjdk.java.net/jdk/pull/249