RFR: JDK-8289512: Fix GCC 12 warnings for adlc output_c.cpp [v2]

[Thomas Stuefe]

> This fixes three warnings in my gcc 12 build on Ubuntu 22.04.

Thomas Stuefe has updated the pull request incrementally with one additional commit since the last revision:

  assert sprint did not overflow

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9335/files
  - new: https://git.openjdk.org/jdk/pull/9335/files/eef0fe64..c3bdc59b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9335&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9335&range=00-01

  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/9335.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9335/head:pull/9335

PR: https://git.openjdk.org/jdk/pull/9335